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MARTINEZ, CECILIA E., PATRICIA G. MENDOZA, FRANCISCO J. ALACRON e HUGO S. GARCIA. "Reactivation of the Lactoperoxidase System during Raw Milk Storage and its Effect on the Characteristics of Pasteurized Milk". Journal of Food Protection 51, n. 7 (1 luglio 1988): 558–61. http://dx.doi.org/10.4315/0362-028x-51.7.558.
Testo completoAbstract (sommario):
The Lactoperoxidase (LP) system was activated periodically during raw milk storage, and after pasteurization. Raw milk was stored at 4°C for 4, 6 or 8 d, and after pasteurization at 8 or 16°C, until a laboratory-trained taste panel reported the presence of off-flavors. When treated milk was stored raw for 4 d, then pasteurized it maintained its quality for 12 d at 8°C; pasteurized control milk had a shelf-life of 9 d only. Shelf-life of pasteurized milk stored at 16°C after pasteurization was 6 d for LP-treated and 5 d for control milk. LP-treated milk that was stored raw for 6 d retained its quality after pasteurization for 11 d at 8°C and 5 d at 16°C, while shelf-life for control milk of this experiment was 5 d at 8°C and 1 d at 16°C. When storage of raw milk was extended to 8 d, control milk showed off-flavors right after pasteurization, whereas LP-treated milk developed a “stored” or “unclean” taste after 1 d of pasteurized storage. Reactivation of the LP system is proposed to extend the shelf-life of pasteurized milk, when raw milk storage for over 2 d is necessary.
2
Semko, Tetyana, e Liudmyla Kolianovska. "HIGH TEMPERATURE PROCESSING OF RAW MILK". Grail of Science, n. 20 (6 ottobre 2022): 80–85. http://dx.doi.org/10.36074/grail-of-science.30.09.2022.013.
Testo completoAbstract (sommario):
Modes of pasteurization of raw milk, which are used in the production of hard rennet cheeses, do not destroy all microflora. Even pasteurization of milk at a temperature of 75...76 °C for 20-25 seconds, which corresponds to the upper limit of heat treatment of raw milk in the production of hard rennet cheeses, provides only 94.6% efficiency of heat-resistant bacteria.
Adopted modes of short-term pasteurization for most rennet cheeses at the level of 72...76 °C with a holding time of 20-25 s allow to achieve the residual amount of bacterial contamination of milk at 72 °C pasteurization mode - 3.2%, at 76 °C pasteurization mode - 0.7 %
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GUY, E. J., K. B. HICKS, J. F. FLANAGAN, T. A. FOGLIA e V. H. HOLSINGER. "Effect of Storage of Raw and Pasteurized Goats' Milk on Flavor Acceptability, Psychrotrophic Bacterial Count, and Content of Organic Acids". Journal of Food Protection 48, n. 2 (1 febbraio 1985): 122–29. http://dx.doi.org/10.4315/0362-028x-48.2.122.
Testo completoAbstract (sommario):
Pasteurization of raw goats' milk either at 63°C for 30 min or 72°C for 15 s within 1 d of milking ensures a better tasting product both initially and during storage at 4.5°C for 6 weeks than if the raw milk is aged for several days at 4.5°C before being pasteurized. Pasteurized milks processed from high-count raw milks aged 1 to 2 weeks had lower acceptability ratings (on a 9-point hedonic scale), which decreased further in cold storage and were independent of bacterial increases in the log phase of growth. Pasteurized milks processed from raw milk 7 or more days old were subject to rapid increases in bacterial numbers in storage if they were trace-contaminated during pasteurization even though initial counts were <100 psychrotrophs/ml. For all raw and pasteurized milks, three peaks were consistently observed from an HPLC analysis designed to monitor some organic acids. Two of the components decreased and the third appeared and increased during storage. Disappearance of one component coincided with appearance of another. These compounds may be associated with loss of flavor quality of the milk since in some instances these changes significantly correlated with the decrease in hedonic ratings of the stored milks.
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Ribeiro Júnior, José Carlos, Aline Marangon de Oliveira, Fernando Godoi Silva, Lorena Natalino Haber Garcia, Cátia Maria de Oliveira Lobo, Bruna Alexandrino, Ronaldo Tamanini e Vanerli Beloti. "Influence of the microbiological quality of raw milk on the shelf life of pasteurized milk". Semina: Ciências Agrárias 40, n. 4 (7 giugno 2019): 1469. http://dx.doi.org/10.5433/1679-0359.2019v40n4p1469.
Testo completoAbstract (sommario):
The dairy industry strives to produce high quality products with high nutritional value as well as to meet the legal standards for longer shelf life. However, these goals are made unfeasible by the poor quality of raw milk produced in some regions of Brazil. Others Brazilian dairy regions, however, already succeed in producing milk with low microbial counts, such as the municipality of Castro, Paraná state, designated as the ‘Brazilian dairy capital’. In order to evaluate the effect of raw milk quality on microbial counts during the shelf life of pasteurized milk, samples were collected from two dairy regions of Paraná: the northern and Castro region, characterized by milk production with high and low microbiological counts, respectively. Samples were experimentally pasteurized and the total microorganism counts were analyzed for 18 days at 7°C, using the Brazilian standard microbiological count limit for pasteurized milk (8 x 104 CFU/mL) as the end of the shelf life. Low microbiological counts in raw milk (Castro) resulted in significantly lower counts shortly after pasteurization and over the entire shelf life, meeting the pasteurized milk standard for 18 days. The temporal evolution in the counts over 18 days for the milks of high and low microbiological count was similar; however, the disparity between the absolute counts between the regions was significant (p < 0.05). Of the milk samples from northern Paraná, four (44.4%) already had counts higher than that of the legislative limit for pasteurized milk immediately after pasteurization. The others (five) reached the maximum microbiological count limit for pasteurized milk on the 6th day after pasteurization. In contrast, the milk from the Castro region remained below the limit throughout the analysis period. Thus, it can be stated that the microbiological quality of raw milk is directly related to the initial count of microorganisms after pasteurization, and that pasteurized milk produced from raw milk with low microbiological counts complies with the Brazilian legislation for 18 days following thermal processing.
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RUAS-MADIEDO, PATRICIA, JUAN CARLOS BADA-GANCEDO, ESTRELLA FERNANDEZ-GARCIA, DOLORES GONZALEZ DE LLANO e CLARA G. de los REYES-GAVILAN. "Preservation of the Microbiological and Biochemical Quality of Raw Milk by Carbon Dioxide Addition: A Pilot-Scale Study". Journal of Food Protection 59, n. 5 (1 maggio 1996): 502–8. http://dx.doi.org/10.4315/0362-028x-59.5.502.
Testo completoAbstract (sommario):
Carbon dioxide treatment of refrigerated raw milk was evaluated as a method for extending storage life by inhibiting growth of psychrotrophic bacteria and other bacterial groups in raw milk. The effect of CO2 acidification followed by degasification and pasteurization on biochemical and microbiological properties of cold stored milk was studied on a pilot scale, Two CO2 treatments (acidification to pH 6.2 and to pH 6.0) were compared with a control (untreated) milk during 4 days of storage at 4°C. Total bacterial counts in the categories of milk established in this study were mainly determined by the proteolytic psychrotroph levels. The inhibitory capability of CO2 was greater in the low-quality than in the high-quality milk category. Acidification at pH 6.0 was more inhibitory than that at pH 6.2, especially against proteolytic psychrotrophs. Neither caseins nor whey proteins were affected by CO2 treatment and pasteurization. Organic acid (orotic, citric, uric, formic, acetic, propionic, and hippuric) concentrations did not change after CO2 treatment, cold storage, or the pasteurization process; the lactic acid content of CO2-treated milks remained constant during the refrigeration time but increased slightly in the control. In general, lower amounts of volatile compounds were produced in CO2-treated milks during refrigeration than in control milk. Ethanol and 2-propanol levels were most affected by degasification and pasteurization. Sensory evaluation revealed no significant differences between CO2-treated milk after degasification and pasteurization and the untreated milk used as control. It was concluded that degasification and pasteurization on a pilot scale eliminated CO2 from milk with minimum detrimental effects on its biochemical and sensory properties, making this process acceptable for milk preservation.
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Soares, C. F., L. M. Fonseca, M. O. Leite e M. C. P. P. Oliveira. "Application of Scharer's quantitative method for the determination of residual alkaline phosphatase activity in standard Minas". Arquivo Brasileiro de Medicina Veterinária e Zootecnia 65, n. 4 (agosto 2013): 1223–30. http://dx.doi.org/10.1590/s0102-09352013000400039.
Testo completoAbstract (sommario):
Milk pasteurization is a critical issue in the dairy industry, and failures in this process can affect final product safety. Scharer's enzymatic method is still traditionally used to verify pasteurization efficiency compliance, and it is based on screening for residual alkaline phosphatase in milk. Although several methods are used to quantify enzymatic activity to assess milk pasteurization efficiency, there is a small amount of published data regarding the use of these methods to quantify alkaline phosphatase in cheese. In this study, the Scharer's modified method was used to determine the levels of residual alkaline phosphatase in standard minas cheese, before and after 20 days of ripening. The cheeses were made using raw or pasteurized milk with the addition of different concentrations of raw milk (0; 0.05%; 0.10%; 0.20%; and 0.50%). In the fresh cheese samples, the method showed a sensitivity of only 0.50% with the addition of raw milk to the pasteurized milk used to make cheese. In addition, levels of up 0.20% of raw milk in pasteurized milk, the concentrations of phenol was inferior to 1μg phenol/g of dairy product which is the preconized indicator value for adequate pasteurization.
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Bhattarai, Bedananda, e Siyaram Prasad Singha. "Quality Evaluation of Milk at Different Levels of Milk Chain System in Makwanpur District, Nepal". Journal of Food Science and Technology Nepal 6 (29 giugno 2013): 80–83. http://dx.doi.org/10.3126/jfstn.v6i0.8265.
Testo completoAbstract (sommario):
This study assessed the quality of raw milk produced by District Milk Producers Co-operative Union (DMPCU) Makawanpur, Nepal. Five different stages (i.e. farmers, co-operative, chilling center, raw milk storage tank and pasteurization) were taken. The study revealed that adulteration was not common problem, however water addition was found to be 2.6% at farmer.s level with increase up to the 18.7% at pasteurization. Decrease in the level of conductivity from 4.32 to 3.25 mS/cm, ash from 0.76 to 0.64 %, fat from 5.38 to 2.96 %, SNF from 9.06 to 7.93%, Lactose 4.44 to 3.81% and protein from 3.1 to 2.5% was noticed from farmer.s to pasteurization level. Increase in Coliform from 4.9 log10 CFU/ml to 5.5 log10 CFU/ml from farmer.s level at raw milk to storage tank was noticed with simultaneous decreased in MBRT from 237 to 99min. Pasteurization reduced Coliform up to zero with increased in MBRT up to 309min. J. Food Sci. Technol. Nepal, Vol. 6 (80-83), 2010 DOI: http://dx.doi.org/10.3126/jfstn.v6i0.8265
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BRADSHAW, JOE G., JAMES T. PEELER e ROBERT M. TWEDT. "Thermal Resistance of Listeria spp. in Milk". Journal of Food Protection 54, n. 1 (1 gennaio 1991): 12–14. http://dx.doi.org/10.4315/0362-028x-54.1.12.
Testo completoAbstract (sommario):
The thermal resistance of one strain each of Listeria ivanovii, L. seeligeri, and L. welshimeri and three L. monocytogenes strains was determined in raw and sterile milk. Listeria spp. suspended in milk at concentrations of 1 × 105 cells/ml were heated at temperatures ranging from 52.2 to 71.1°C for various contact times. The heat resistance of L. monocytogenes appeared somewhat greater than that of the other Listeria spp. in both milks, but the difference was not statistically significant (α = 0.05). High-temperature, short-time processing is adequate for pasteurization of raw milk.
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BYRNE, R. D., e J. R. BISHOP. "Evaluation of a Dry Medium Culture Plate (3M Petrifilm AC) for Laboratory Pasteurized Counts". Journal of Food Protection 54, n. 4 (1 aprile 1991): 308–9. http://dx.doi.org/10.4315/0362-028x-54.4.308.
Testo completoAbstract (sommario):
In this study Petrifilm AC was evaluated for its ability to enumerate thermoduric bacteria in raw milk by the laboratory pasteurized count (LPC). LPC's were conducted on agar pour plates and Petrifilm plates. Both plating techniques were conducted immediately following laboratory pasteurization, and plating was also conducted after incubations of 2 and 4 h at room temperature. Uninoculated raw milk samples, raw milk inoculated with Bacilluscereus, Micrococcus luteus, and raw milk isolates (Streptococcus, Corynebacterium, and Micrococcus species) were enumerated. A total of 270 samples was analyzed. Uninoculated raw milk samples and raw milk samples inoculated with B. cereus, Corynebacterium, Streptococcus, and some Micrococcus species showed no significant difference between agar pour plates and Petrifilm AC. Other Micrococcus species were recovered at lower numbers on the Petrifilm after laboratory pasteurization. Some of these were comparable to the agar plates after a 4-h incubation at room temperature. This study indicates that Petrifilm AC could be used in place of agar pour plates to conduct the LPC.
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Novella-Rodríguez, Sonia, M. Teresa Veciana-Nogués, Artur X. Roig-Sagués, Antonio J. Trujillo-Mesa e M. Carmen Vidal-Carou. "Evaluation of biogenic amines and microbial counts throughout the ripening of goat cheeses from pasteurized and raw milk". Journal of Dairy Research 71, n. 2 (maggio 2004): 245–52. http://dx.doi.org/10.1017/s0022029904000147.
Testo completoAbstract (sommario):
The effect of the hygienic quality of milk on changes in microbial counts and biogenic amine content was evaluated during ripening of goat cheeses manufactured from pasteurized and raw milks at 1, 14, 30, 60 and 90 d. The original milk, rennet, curd and whey were also included in the study. The pH, salt content and extent of proteolysis in the cheese were also evaluated. Spermidine and spermine were the main amines in raw milk, while they were minor amines in cheeses. Other amines increased markedly during ripening, tyramine being the main amine in cheese made from raw milk and cadaverine and putrescine in those produced from pasteurized milk. Enterobacteriaceae counts decreased during ripening whereas those of lactic acid bacteria increased, especially lactobacilli and enterococci. Cheese made from raw milk showed higher microbial counts during ripening than those made from pasteurized milk, especially for Enterobacteriaceae and enterococci, counts being 2 or 3 log units higher. Raw milk cheese showed remarkably higher biogenic amines compared with pasteurized milk cheeses. Therefore, pasteurization of milk causes a decrease in final biogenic amine content of cheese as a result of the reduction of its microbial counts.
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Nurfarhana Syed Malik, Mohd. Nizam Lani e Fauziah Tufail Ahmad. "Stability of Lactic Acid Bacteria in Pasteurized Cow’s and Goat’s Milk". Universiti Malaysia Terengganu Journal of Undergraduate Research 1, n. 4 (31 ottobre 2019): 77–82. http://dx.doi.org/10.46754/umtjur.v1i4.94.
Testo completoAbstract (sommario):
This study was done to determine the effect of pasteurization on the stability of lactic acid bacteria (LAB) and its enzyme in raw and pasteurized cow’s and goat’s milk. The total viable count for plate count of the bacterial growth concentration was higher in both pasteurized cow’s and goat’s milk at 2.48 log CFU/ml. This is followed by raw cow’s milk (1.59 log CFU/ml) and raw goat’s milk (0.65 log CFU/ml). Lactic acid bacteria (LAB) was found to be similar in both raw cow’s and goat’s milk (p>0.05), and pasteurized milk of both animals also contained the same amount of LAB (p>0.05). LAB was still detected in pasteurized milk (p<0.05), indicating the stability of LAB against the pasteurization temperature. Interestingly, based on API ZYM assay kit results, there were nine different enzymes detected in all samples, which were leucinearylamidase, valinearylamidase,cystinearylamidase, trypsin, α-chymotrypsin, naphthol-AS-BI-phosphohydrolase, α-glucosidase, β-glucosidaseand acid phosphatise. The results revealed that different types of lactic acid bacteria were detected in treated and non-treated milk samples produced by different animals, indicating the different stability levels of LAB against pasteurization.
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MacDONALD, LAUREN E., JAMES BRETT, DAVID KELTON, SHANNON E. MAJOWICZ, KATE SNEDEKER e JAN M. SARGEANT. "A Systematic Review and Meta-Analysis of the Effects of Pasteurization on Milk Vitamins, and Evidence for Raw Milk Consumption and Other Health-Related Outcomes". Journal of Food Protection 74, n. 11 (1 novembre 2011): 1814–32. http://dx.doi.org/10.4315/0362-028x.jfp-10-269.
Testo completoAbstract (sommario):
Pasteurization of milk ensures safety for human consumption by reducing the number of viable pathogenic bacteria. Although the public health benefits of pasteurization are well established, pro–raw milk advocate organizations continue to promote raw milk as “nature's perfect food.” Advocacy groups' claims include statements that pasteurization destroys important vitamins and that raw milk consumption can prevent and treat allergies, cancer, and lactose intolerance. A systematic review and meta-analysis was completed to summarize available evidence for these selected claims. Forty studies assessing the effects of pasteurization on vitamin levels were found. Qualitatively, vitamins B12 and E decreased following pasteurization, and vitamin A increased. Random effects meta-analysis revealed no significant effect of pasteurization on vitamin B6 concentrations (standardized mean difference [SMD], −2.66; 95% confidence interval [CI], −5.40, 0.8; P = 0.06) but a decrease in concentrations of vitamins B1 (SMD, −1.77; 95% CI, −2.57, −0.96; P < 0.001), B2 (SMD, −0.41; 95% CI, −0.81, −0.01; P < 0.05), C (SMD, −2.13; 95% CI, −3.52, −0.74; P < 0.01), and folate (SMD, −11.99; 95% CI, −20.95, −3.03; P < 0.01). The effect of pasteurization on milk's nutritive value was minimal because many of these vitamins are naturally found in relatively low levels. However, milk is an important dietary source of vitamin B2, and the impact of heat treatment should be further considered. Raw milk consumption may have a protective association with allergy development (six studies), although this relationship may be potentially confounded by other farming-related factors. Raw milk consumption was not associated with cancer (two studies) or lactose intolerance (one study). Overall, these findings should be interpreted with caution given the poor quality of reported methodology in many of the included studies.
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Baral, Sasmita, e Dhiraj Kumar Nanda. "Risk and benefits of consuming raw (unpackaged) and pasteurized (packaged) milk". DRC Sustainable Future: Journal of Environment, Agriculture, and Energy 1, n. 1 (5 marzo 2020): 23–32. http://dx.doi.org/10.37281/drcsf/1.1.4.
Testo completoAbstract (sommario):
The aim of this review is to overview important literature data on milk and its composition, methodology of quality assurance throughout its processing and preservation, and to compare risks and benefits of consuming raw (unpackaged) and pasteurized (packaged) milk. Milk contamination risks are of various types, including physical contamination (foreign components, such as manure, feed, dust, pieces of broken glass, strands of hair, wood, plastic, or metal chips), chemical impurities (antibiotics, hormones, pesticides, detergents, or heavy metal residues), and microbiological agents (germs and somatic cells). Our study addresses the quality and safety of raw and pasteurized milk consumed by humans. If one considers risks and benefits simultaneously, there are many pros and cons of consuming raw and pasteurized milk. One can conclude that pasteurized milk is more appropriate for consumption as compared to the lower quality raw milk. For manufacturing high quality pasteurized milk, one should implement good hygienic practices, proper pasteurization process, as well as pre and post pasteurization preservation.
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Ahmad Thania, Siti Nur Aqeela ‘Illiyin, e Mohd Tarmizan Ibrahim. "Treated Cow Milk Quality Analysis in High-Temperature Short Time (HTST) Thermal Treatment using F-Value and Methylene Blue Reduction Test (MBRT)". Journal Of Agrobiotechnology 12, n. 1S (30 settembre 2021): 124–32. http://dx.doi.org/10.37231/jab.2021.12.1s.277.
Testo completoAbstract (sommario):
This study was conducted to evaluate raw and pasteurized cow milk regarding physical properties, microbiological quality, and lethality value ofMycobacterium Paratuberculosis(MAP)at different temperature and time combinations of the pasteurization process.Cow milk samples were pasteurized at high-temperature (70°C, 75°C, and 81°C) and short-time (15s and 25s) high temperature and short time (HTST) combinations. Raw and pasteurized (HTST) cow milk was analyzed, while commercial cow milk that undergo proses (HTST) was used as control. High-temperature short time (HTST) pasteurization showed a significant effect on the colour of raw and pasteurized cow milk (p<0.05) at every temperature. In addition, cow milk also indicated an increase in lightness and yellowness after HTST pasteurization.The microbiological quality of raw, pasteurized, and commercial cow milk is evaluated using the Methylene Blue Reduction (MBRT) test, a common, rapid, simple, and inexpensive method for microbiological quality evaluation.The MBRT on raw milk samples revealed that it was of poor quality. On the other hand, all pasteurized samples were good quality, and the commercial sample was excellent.Based on the evaluated F-values, the most suitable temperature and time combinationsin this study was 70°C and 25s.
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Pappa, Eleni C., Thomas G. Bontinis, John Samelis e Kyriaki Sotirakoglou. "Assessment of the Microbiological Quality and Biochemical Parameters of Traditional Hard Xinotyri Cheese Made from Raw or Pasteurized Goat Milk". Fermentation 8, n. 1 (4 gennaio 2022): 20. http://dx.doi.org/10.3390/fermentation8010020.
Testo completoAbstract (sommario):
Traditional hard Xinotyri cheese was manufactured using raw or pasteurized goat milk, without starter cultures, and the changes in microbiological and biochemical characteristics were studied during ripening and storage. Mesophilic lactic acid bacteria (LAB) predominated (>8.5 log CFU/g) in freshly fermented Xinotyri cheeses (pH 4.5–4.6), regardless of milk pasteurization. Enterobacteria, pseudomonads and staphylococci were suppressed below 6 and 4–5 log CFU/g in fresh cheeses from raw and pasteurized milk, respectively. Salmonella and Listeria spp. were absent in 25 g cheese samples. Coagulase-positive staphylococci exceeded the 5-log safety threshold in fresh raw milk cheeses, which also had 10-fold higher levels of enterococci than pasteurized milk cheeses. Non-LAB groups declined <100 CFU/g, whereas yeasts increased to 5–6 log CFU/g in both cheeses during ripening. Milk pasteurization affected the protein, fat, ash, moisture, nitrogen fractions, total free fatty acids and total free amino acids content of cheeses. Primary proteolysis, detectable by urea-PAGE, was more intense in raw milk cheeses than in pasteurized milk cheeses. However, the hydrophilic and hydrophobic peptides and their ratio in the water-soluble fraction were similar in both cheeses. Cheeses discriminated clearly according to the milk kind (raw, pasteurized) and the stage of ripening, based on the examined biochemical characteristics.
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KLOTZ, V., ART HILL, K. WARRINER, M. GRIFFITHS e J. ODUMERU. "Assessment of the Colorimetric and Fluorometric Assays for Alkaline Phosphatase Activity in Cow's, Goat's, and Sheep's Milk". Journal of Food Protection 71, n. 9 (1 settembre 2008): 1884–88. http://dx.doi.org/10.4315/0362-028x-71.9.1884.
Testo completoAbstract (sommario):
Raw milk is a well-established vehicle for the carriage of human pathogens, and many regulatory bodies have consequently mandated compulsory pasteurization as a food safety intervention. The residual activity of alkaline phosphatase (ALP) has historically been used to verify the adequacy of pasteurization of cow's milk. However, there is uncertainty on how the current ALP standards and methods of analysis can be applied to sheep's and goat's milk, which naturally contain different levels of the enzyme than that found in cow's milk. The official ALP methods applied in Canada (colorimetric assay; MFO-3) and in the United States (Fluorophos) were assessed for their ability to detect enzyme activity in raw and pasteurized milk derived from cows, sheep, and goats. The detection limit and the limit of quantitation were 0.8 and 2.02 μg/ml phenol, respectively, for the MFO-3 method and 43 and 85 mU/liter, respectively, for the Fluorophos method. The average ALP levels in raw goat's, cow's, and sheep's milk were 165, 1,562, and 3,512 μg/ml phenol, respectively. Raw milk detection limits, which correspond to raw milk phosphatase levels, were 0.051, 0.485, and 0.023% in cow's, goat's, and sheep's milk, respectively, for the MFO-3 method and 0.007, 0.070, and 0.004%, respectively, for the Fluorophos method. Although both methods can be used for ALP determination in cow's, goat's, and sheep's milk, the Fluorophos assay was superior to the colorimetric MFO-3 method based on sensitivity and time required to complete the analysis.
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Centeno, Juan A., Estrella Fernández-García, Pilar Gaya, Javier Tomillo, Margarita Medina e Manuel Nuñez. "Volatile compounds in cheeses made from raw ewes' milk ripened with a lactic culture". Journal of Dairy Research 71, n. 3 (23 luglio 2004): 380–84. http://dx.doi.org/10.1017/s0022029904000214.
Testo completoAbstract (sommario):
In some European regions ewes' milk is transformed into cheese without a previous heat treatment. The microbiota and the native enzymes present in raw milk are considered to be responsible for the characteristic strong flavour of raw ewes' milk cheeses (Nuñez et al. 1989). Although pasteurization ensures a higher uniformity of the product, heat treatment of ewes' milk may impair the sensory characteristics of cheeses (Gaya et al. 1990).
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CHUMAKOVA, IRINA, GALINA DONSKAYA, EKATERINA DOBRIYAN e VIKTOR DROZHZHIN. "ANTIOXIDANT ACTIVITY OF RAW MILK AND MILK PROTEIN FRACTIONS". Elektrotekhnologii i elektrooborudovanie v APK 4, n. 41 (dicembre 2020): 111–18. http://dx.doi.org/10.22314/2658-4859-2020-67-4-111-118.
Testo completoAbstract (sommario):
Compounds with antioxidant properties act as stabilizers of biological membranes and prevent the development of free-radical chain processes that lead to the development of severe diseases. Cow’s milk shows antioxidant activity due to whey proteins. Heat treatment used in dairy production technology can inhibit the antioxidant properties of milk proteins. Preserving the natural properties of milk is an urgent task. (Research purpose) The research purpose is in studying the antioxidant activity of raw milk and protein fractions isolated from it with optimal preservation of the activity of whey proteins. (Materials and methods) Authors received raw milk from an individual farm in the Moscow region. The physicochemical parameters of milk and whey were assessed by standardized methods; the fractional composition of proteins was assessed by high-performance liquid chromatography; and the antioxidant activity (total content of water-soluble antioxidants) of milk and protein fractions isolated from it assessed by amperometric method. Milk proteins were coagulated using rennet and calcium chloride. Protein fractions were separated by centrifugation (15,000 revolutions per minute) for 90 minutes. (Results and discussion) The article presents the physical and chemical parameters of raw whole and skimmed milk. The fractional composition of native serum proteins with a predominance of beta-lactoglobulin was studied. The method of milk protein isolation by rennet-calcium method was worked out at a minimum temperature of 38-40 degrees Celsius. (Conclusions) The article presents the composition of raw milk. The article presents the developed optimal conditions for isolation of native proteins from raw skim milk. The antioxidant activity of raw milk, casein fraction and whey was assessed. To maximize the preservation of the antioxidant activity of biologically active whey proteins, it is necessary to reduce the generally accepted pasteurization temperatures of milk (75-95 degrees Celsius), while at the same time searching for new methods of decontamination of milk from foreign microflora.
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Hartle, Jennifer C., Ronald S. Cohen, Pauline Sakamoto, Dana Boyd Barr e Suzan L. Carmichael. "Chemical Contaminants in Raw and Pasteurized Human Milk". Journal of Human Lactation 34, n. 2 (30 marzo 2018): 340–49. http://dx.doi.org/10.1177/0890334418759308.
Testo completoAbstract (sommario):
Background: Environmental contaminants ranging from legacy chemicals like p,p’-dichlorodiphenyltrichloroethane (DDT) to emerging chemicals like phthalates are ubiquitous. Research aims/questions: This research aims to examine the presence and co-occurrence of contaminants in human milk and effects of pasteurization on human milk chemical contaminants. Methods: We analyzed human milk donated by 21 women to a milk bank for 23 chemicals, including the persistent organic pollutants (POPs) polychlorinated biphenyls (PCBs), polybrominated diphenyl ethers (PBDEs), dichlorodiphenyltrichloroethane (DDT), and dichlorodiphenyldichloroethylene (DDE) isomers that are known to sequester in adipose tissue, along with the current-use and nonpersistent pesticides chlorpyrifos and permethrin, phthalates, and bisphenol A (BPA). Human milk was analyzed raw and pasteurized for these chemicals using gas chromatography–tandem mass spectrometry for the POPs and high-performance liquid chromatography–tandem mass spectrometry for non-POPs. Results: Within the different chemical classes, PBDE47, PCB153, ppDDE, and MEHHP (phthalate metabolite) had the highest median concentrations and were observed in all samples. We also observed chlorpyrifos and BPA in all samples and permethrin in 90% of the samples tested. Only two chemicals, chlorpyrifos and permethrin, were susceptible to substantial degradation from pasteurization, a standard method for processing donated human milk. Conclusion: We detected 19 of 23 chemicals in all of our prepasteurized milk and 18 of 23 chemicals in all of our pasteurized milk. Pasteurization did not affect the presence of most of the chemicals. Future research should continue to explore human milk for potential chemical contamination and as a means to surveil exposures among women and children.
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Tripaldi, Carmela, Simona Rinaldi, Giuliano Palocci, Sabrina Di Giovanni, Salvatore Claps e Luca Buttazzoni. "Effect of Storage and Heat Treatment of Milk Destined for Cheese Production on Its Oxidative Characteristics". Dairy 2, n. 4 (18 ottobre 2021): 585–601. http://dx.doi.org/10.3390/dairy2040046.
Testo completoAbstract (sommario):
The oxidative stability of milk and dairy products is a very interesting topic for the dairy industry due to the growing demand for foods containing bioactive compounds with positive health effects. The aim was to evaluate the oxidative stability of milk intended for cheese production. The effect of storage time, heat pre-treatment, and milk pasteurization temperature on the characteristics of milk and cheese was investigated. The cheese samples were produced with pasteurized milk at both 72 and 77 °C for a time of 15 s using three types of milk: raw fresh milk processed within 48 h of milking, raw stored milk processed within 96 h, and thermized milk that was heat-treated upon arrival at the dairy and processed within 96 h of milking. In total, three repetitions were carried out for each type of milk and pasteurization. Samples of milk before and after pasteurization and cheese at 14 days of storage were analyzed. Antioxidant activity decreased from starting milk to milk after pasteurization to final cheese. The longer storage time of the milk had significant effects on the antioxidant stability of the cheese (64.95 vs. 59.05% of antioxidant activity). Thermization of the milk further reduced the stability of the cheese (54.05% of antioxidant activity). The greater antioxidant stability of fresh milk and cheeses produced with fresh milk is the first result that encourages the production of cheese from a milk that best preserves its original characteristics.
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JOHNSON, ERIC A., JOHN H. NELSON e MARK JOHNSON. "Microbiological Safety of Cheese Made from Heat-Treated Milk, Part III. Technology, Discussion, Recommendations, Bibliography". Journal of Food Protection 53, n. 7 (1 luglio 1990): 610–23. http://dx.doi.org/10.4315/0362-028x-53.7.610.
Testo completoAbstract (sommario):
Heat treatment or pasteurization does not adversely affect the cheesemaking process or the resulting physical properties of the cheese. Both types of heat-treatments can correct chemical changes that occur in cold stored raw milk. Thermization on the farm may help control psychrotrophic bacteria in cold stored milk. Some denaturation of whey protein does occur during pasteurization. Heat treatments slightly above current minimum pasteurization requirements can cause body/texture and moisture control problems in cheese. Loss of functionality can adversely affect the marketing of whey protein products. Cheeses made from pasteurized milk ripen more slowly and usually do not exhibit the flavor intensity of cheeses made from raw or heat-treated milk. Swiss and hard Italian type cheese, whose traditional flavor results in part from native milk enzymes and microflora, would also be adversely affected if milk pasteurization for cheesemaking were mandatory. The quality of cheese made from pasteurized milk is consistently better than cheese made from raw milk as evidenced by fewer body and flavor defects consequent to the growth of undesirable bacteria. Either pasteurization or heat-treatment enables improved uniform process control and quality during cheesemaking. Pathogens were prioritized as high, medium, or low risk in cheese. Three organisms, Salmonella, Listeria monocytogenes and enteropathogenic Escherichia coli were judged to be high risk threats to the cheese industry. Staphylococcus aureus was listed as low risk because growth and toxin production is readily suppressed by lactic cultures and acidity (pH) control in cheese. Three actions are recommended:Establish a guideline for minimum heat-treatment of milk for cheesemaking: 64.4°C (148°F) for 16 s or equivalent with adequate process control.Evaluate current safety technology and practices used for cheese manufacture. Support research with primary emphasis on the combined effect of heat-treatment and other current cheese technologies.Evaluate technologies not currently utilized in cheese manufacture for safety potential.
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Gagara, Mariama Hima, Philippe Sessou, Francois Dossa, Serge Ahounou, Paulin Azokpota, Issaka Youssao, Abdoulaye Soumana Gouro e Souaibou Farougou. "A Study on the Indigenous Methods of Processing Milk in Niger". Current Agriculture Research Journal 7, n. 2 (10 luglio 2019): 213–23. http://dx.doi.org/10.12944/carj.7.2.09.
Testo completoAbstract (sommario):
The purpose of this study was to identify the methods of processing and preserving of local milk within the area of Liptako-Gourma in Niger. A survey was conducted and data were collected from 600 people involved in dairy sector, comprising of 59% producers, 28.7% collectors and 12.3% processors. The study also revealed two main methods of milk processing that is pasteurization and fermentation comprising of natural/spontaneous fermentation done by 42.9% and fermentation method by backslopping practiced by 57.10% of processors. In addition, four methods of preserving milk were identified, including the cooling of raw milk, pasteurized or fermented milk, the pasteurization of raw milk itself for sale or for processing, the fermentation of raw milk or pasteurized milk and the addition of guinea pepper pods to fermented milk. Milk processing and preserving technology remains traditional with no compliance to hygiene good practices and the use of old material being limited most often to the strict minimum. Due to these results, attention should be paid to the training of the processors on hygiene and good practices at all levels of the local milk industry in order to improve traditional methods related to the processing and preserving of local milk and thus raising the quality of the dairy products in terms of microbiological safety.
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Ruas-Madiedo, Patricia, Juan Carlos Bada-Gancedo, Teresa Delgado, Miguel Gueimonde e Clara G. de los Reyes-Gavilán. "Proteolysis in rennet-coagulated Spanish hard cheeses made from milk preserved by refrigeration and addition of carbon dioxide". Journal of Dairy Research 70, n. 1 (febbraio 2003): 115–22. http://dx.doi.org/10.1017/s0022029902005952.
Testo completoAbstract (sommario):
On-farm refrigeration of milk reduces the growth rate of mesophilic bacteria so allowing longer storage time of raw milk before processing. However, refrigeration creates a selective pressure favouring the multiplication of psychrotrophic bacteria present as normal contaminants in raw milk. Psychrotrophs are killed by most of the currently employed pasteurization and sterilization treatments of milk but they can produce extracellular heat-stable proteinases and lipases, which are capable of degrading various milk components, affecting the storage-life of heat-processed milk and the quality of dairy products (Champagne et al. 1994; Shah, 1994).
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STEELE, MARINA L., W. BRUCE McNAB, CASE POPPE, MANSEL W. GRIFFITHS, SHU CHEN, STEPHANIE A. DEGRANDIS, LYNNE C. FRUHNER, CAROLYN A. LARKIN, JOHN A. LYNCH e JOSEPH A. ODUMERU. "Survey of Ontario Bulk Tank Raw Milk for Food-Borne Pathogens". Journal of Food Protection 60, n. 11 (1 novembre 1997): 1341–46. http://dx.doi.org/10.4315/0362-028x-60.11.1341.
Testo completoAbstract (sommario):
Raw (unpasteurized) milk can be a source of food-borne pathogens. Raw milk consumption results in sporadic disease outbreaks. Pasteurization is designed to destroy all bacterial pathogens common to raw milk, excluding spore-forming bacteria and possibly Mycobacterium paratuberculosis, but some people continue to drink raw milk, believing it to be safe. Current methods for assessing the bacteriological quality of raw milk, such as aerobic plate counts, are not usually designed to detect specific pathogens. The objective of this study was to estimate the proportion of pick-ups (loads of raw milk from a single farm bulk tank) from Ontario farm bulk tanks that contained Listeria monocytogenes. Salmonella spp., Campylobacter spp., and/or verotoxigenic Escherichia coli (VTEC). Samples from 1,720 pick-ups of raw milk were tested for the presence of these pathogens, and 47 L. monocytogenes, three Salmonella spp., eight Campylobacter spp., and 15 VTEC isolates were detected, representing 2.73, 0.17, 0.47, and 0.87% of milk samples, respectively. Estimates of the proportion of theoretical tanker truck loads of pooled raw milk contaminated with pathogens ranged from a low of 0.51 % of tankers containing raw milk from 3 bulk tanks being contaminated with Salmonella spp. to a high of 34.41 % of tankers containing raw milk from 10 bulk tanks being contaminated with at least one of the pathogens. Associations between the presence of pathogens and raw milk sample characteristics were investigated. The mean somatic cell count was higher among VTEC- or L. monocytogenes-positive samples, and the mean aerobic plate count was found to be higher among L. monocytogenes-positive samples. These results confirm the presence of bacterial food pathogens in raw milk and emphasize the importance of continued diligence in the application of hygiene programs within dairies and the separation of raw milk from pasteurized milk and milk products.
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Popovic-Vranjes, Anka, Milka Popovic e Marija Jevtic. "Raw milk consumption and health". Srpski arhiv za celokupno lekarstvo 143, n. 1-2 (2015): 87–92. http://dx.doi.org/10.2298/sarh1502087p.
Testo completoAbstract (sommario):
Contrary to the safe practices of milk pasteurization or sterilization, which effectively reduce foodborne outbreaks incidence associated with raw milk and dairy products use, outbreaks caused by such products continue to occur. Despite this fact, a worldwide movement advocating for the rights of raw milk and cheese selling and consumption, due to their specific nutritive characteristics, has strengthened significantly in recent years. Traditional agricultural manufacturers from Serbia still sell products related to thermally unprocessed milk, such as cottage cheese and raw cream. In AP Vojvodina during the period of 1981-2010 a total of 179 foodborne outbreaks were reported, where the incriminated cause of the outbreak were milk or diary. In 126 (70.39%) outbreaks, totaling 2276 sick individuals and one casualty, it was confirmed that the incriminated food was from the group of dairy products. In 48 instances (26.82%), bacteriological tests confirmed that milk and dairy products were excluded as the outbreak causes, while in another 5 (2.79%) outbreaks, microbiological analysis of food failed to confirm any relation to the actual epidemiological instances. In some cases, bacteriological testing of incriminated foods was not possible. In the cases of outbreaks associated with the consumption of milk and dairy products, traditional raw milk products were cited as being used. Consumption of unpasteurized milk and cheese represents public health threat. National and international rules ensuring use of safe products for human consumption have to set rules of trade of thermally processed milk and products on the market.
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Acharya, Sarda, Nabin Kishor Bimali, Soni Shrestha e Binod Lekhak. "Bacterial Analysis of Different Types of Milk (Pasteurized, Unpasteurized and Raw Milk) Consumed in Kathmandu Valley". Tribhuvan University Journal of Microbiology 4 (16 novembre 2018): 32–38. http://dx.doi.org/10.3126/tujm.v4i0.21674.
Testo completoAbstract (sommario):
Objectives: The presence of pathogenic bacteria in milk is the major public health concern resulting in food borne illness. The aim of this study is to determine the microbial quality of three different types of milk consumed in Kathmandu Valley with respect to the acceptable standard guideline and measure the antibiotic susceptibility pattern of the Escherichia coli and Staphylococcus aureus isolates.Methods: A total of 66 samples (16 pasteurized, 25 unpasteurized and 25 raw milk) were collected from various sites of Kathmandu Valley. Those samples were subjected for total plate count and total coliform count by pour plate method. Furthermore, identification was made for the presence of E. coli and S. aureus with biochemical tests.Results: The mean total plate count (TPC) of pasteurized, unpasteurized and raw milk was 1.2X106 cfu/ml, 2.3 X 107 cfu/ml and 2.0 X 107 cfu/ml respectively. And, the mean total coliform count (TCC) of pasteurized, unpasteurized and raw milk was 2.9 X 104cfu/ml, 6.3 X 105 cfu/ml and 1.6 X 105 cfu/ ml respectively. Coliforms were detected in 50%, 84% and 56% of the pasteurized, unpasteurized and raw milk sample respectively. E. coli and S. aureus were isolated from 18.8% and 12.5% of pasteurized, 40% and 16% of unpasteurized and 20% and 24% of the raw milk samples respectively. Among total E. coli isolates (n=18), 16.7% were susceptible to ampicillin whereas 100% isolates were susceptible to other tested antibiotics. Similarly, 33.3% and 66.7% of the isolated S. aureus were susceptible to penicillin and cefoxitin respectively, whereas all S. aureus isolates were sensitive to all other antibiotics.Conclusion: The mean value of TPC and TCC of pasteurized and raw milk exceed the standard guideline by FDA. Higher total plate count and presence of coliforms (also E. coli) and S. aureus in this study necessitates the close monitoring of the pasteurization process and post pasteurization process (packaging, transportation, storage etc.).
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O'Reilly, Ciara E., Lisa O'Connor, Wayne Anderson, Peter Harvey, Irene R. Grant, John Donaghy, Michael Rowe e Pat O'Mahony. "Surveillance of Bulk Raw and Commercially Pasteurized Cows' Milk from Approved Irish Liquid-Milk Pasteurization Plants To Determine the Incidence of Mycobacterium paratuberculosis". Applied and Environmental Microbiology 70, n. 9 (settembre 2004): 5138–44. http://dx.doi.org/10.1128/aem.70.9.5138-5144.2004.
Testo completoAbstract (sommario):
ABSTRACT Over the 13-month period from October 2000 to November 2001 (inclusive), the Food Safety Authority of Ireland (FSAI) carried out surveillance of Irish bulk raw (n = 389) and commercially pasteurized (n = 357) liquid-milk supplies to determine the incidence of Mycobacterium paratuberculosis. The pasteurization time-temperature conditions were recorded for all pasteurized samples. Overall, 56% of whole-milk pasteurized samples had been heat treated at or above a time-temperature combination of 75°C for 25 s. All analyses were undertaken at the Department of Food Science (Food Microbiology) laboratory at Queen's University Belfast. Each milk sample was subjected to two tests for M. paratuberculosis: immunomagnetic separation-PCR (IMS-PCR; to detect the presence of M. paratuberculosis cells, live or dead) and chemical decontamination and culture (to confirm the presence of viable M. paratuberculosis). Overall, M. paratuberculosis DNA was detected by IMS-PCR in 50 (12.9%; 95% confidence interval, 9.9 to 16.5%) raw-milk samples and 35 (9.8%; 95% confidence interval, 7.1 to 13.3%) pasteurized-milk samples. Confirmed M. paratuberculosis was cultured from one raw-milk sample and no pasteurized-milk samples. It is concluded that M. paratuberculosis DNA is occasionally present at low levels in both raw and commercially pasteurized cows' milk. However, since no viable M. paratuberculosis was isolated from commercially pasteurized cows' milk on retail sale in the Republic of Ireland, current pasteurization procedures are considered to be effective.
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Abbring, Suzanne, Phillip A. Engen, Ankur Naqib, Stefan J. Green, Johan Garssen, Ali Keshavarzian e Betty C. A. M. van Esch. "Raw Milk-Induced Protection against Food Allergic Symptoms in Mice Is Accompanied by Shifts in Microbial Community Structure". International Journal of Molecular Sciences 22, n. 7 (26 marzo 2021): 3417. http://dx.doi.org/10.3390/ijms22073417.
Testo completoAbstract (sommario):
The mechanism underlying the allergy-protective effects of raw cow’s milk is still unknown, but the modulation of the gut microbiome may play a role. The effects of consuming raw cow’s milk or processed milk on fecal microbial communities were therefore characterized in an experimental murine model. C3H/HeOuJ mice were treated with raw milk, pasteurized milk, skimmed raw milk, pasteurized milk supplemented with alkaline phosphatase (ALP), or phosphate-buffered saline (PBS) for eight days prior to sensitization and challenge with ovalbumin (OVA). Fecal samples were collected after milk exposure and after OVA sensitization, and microbiomes were characterized using 16S ribosomal RNA gene amplicon sequencing. Treatment with raw milk prior to OVA sensitization increased the relative abundance of putative butyrate-producing bacteria from the taxa Lachnospiraceae UCG-001, Lachnospiraceae UCG-008, and Ruminiclostridium 5 (Clostridial clusters XIVa and IV), while it decreased the relative abundance of Proteobacterial genera such as Parasutterella, a putative pro-inflammatory bacterial genus. This effect was observed after eight days of raw milk exposure and became more pronounced five weeks later, after allergic sensitization in the absence of milk. Similar trends were observed after treatment with skimmed raw milk. Conversely, the feeding of pasteurized milk led to a loss of allergy protection and a putative dysbiotic microbiome. The addition of ALP to pasteurized milk restored the protective effect observed with raw milk and mitigated some of the microbial community alterations associated with milk pasteurization. Raw milk-induced protection against food allergic symptoms in mice is accompanied by an increased relative abundance of putative butyrate-producing Clostridiales and a decreased relative abundance of putative pro-inflammatory Proteobacteria. Given the safety concerns regarding raw milk consumption, this knowledge is key for the development of new, microbiologically safe, preventive strategies to reduce the incidence of allergic diseases.
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Gaya, Pilar, Carmen Sánchez, Manuel Nuñez e Estrella Fernández-García. "Proteolysis during ripening of Manchego cheese made from raw or pasteurized ewes' milk. Seasonal variation". Journal of Dairy Research 72, n. 3 (23 maggio 2005): 287–95. http://dx.doi.org/10.1017/s0022029905001019.
Testo completoAbstract (sommario):
Changes in nitrogen compounds during ripening of 40 batches of Manchego cheese made from raw milk (24 batches) or pasteurized milk (16 batches) at five different dairies throughout the year were investigated. After ripening for six months, degradation of p-κ- and β-caseins was more intense in raw milk cheese and degradation of αs2-casein in pasteurized milk cheese. Milk pasteurization had no significant effect on breakdown of αs1-casein. Hydrophobic peptide content did not differ between raw and pasteurized milk cheese, whereas hydrophilic peptide content was higher in raw milk cheese. There were no significant differences between seasons for residual caseins, but hydrophobic peptides were at a higher level in cheese made in autumn and winter and hydrophilic peptides in cheese made in winter and spring. Raw milk cheese had a higher content of total free amino acids and of most individual free amino acids than pasteurized milk cheese. The relative percentages of the individual free amino acids were significantly different for raw milk and pasteurized milk cheeses. The relative percentages of Lys and Ile increased, while those of Val, Leu and Phe decreased during ripening. There were also seasonal variations within the relative percentages of free amino acids. In raw milk cheeses, Asp and Cys were relatively more abundant in those made in autumn, Glu and Arg in cheeses made in winter, and Lys and Ile in cheeses made in spring and summer. Biogenic amines were detected only in raw milk cheese, with the highest levels of histamine, tryptamine and tyramine in cheeses made in spring, winter and spring, respectively.
30
Hanuš, Oto, Kristýna Hanušová, Marcela Vyletělová, Tomáš Kopec, Libor Janů e Jaroslav Kopecký. "Selected abiotic factors that influence raw cow milk freezing point depression". Acta Veterinaria Brno 81, n. 1 (2012): 49–55. http://dx.doi.org/10.2754/avb201281010049.
Testo completoAbstract (sommario):
Freezing point depression (FPD) is an important property of milk that is influenced primarily by milk components connected to osmotic pressure. Under certain conditions it is possible to detect the addition of water to milk. It is necessary to have the right FPD limit in legislation for milk quality control. The aim of this study was to improve the estimation procedure of this limit. Apart from factors related to dairy cow nutrition, cattle breed and milk yield, it is important to take into account CO2 (6%), water steam evaporation and pasteurization under technological conditions. Bulk milk samples (1, 30, 6, 6, 10, 1 according to experiment) from Holstein and Czech Fleckvieh breed (1:1) were used in the experiments and technologically treated. The effects of water addition (water saturated and unsaturated by CO2), carbon dioxide evaporation and pasteurization (80 °C for 22 min) were quantified. Pasteurization aggravation of FPD was -0.00394 ± 0.00171 ºC (P < 0.001). Aggravation due to carbon dioxide evaporation could be -0.00383 ± 0.00095 ºC (P < 0.001) depending on practice. Increase in FPD is recorded after milking during technological procedures of milk storage, mixing, pumping, transport shaking and warming. During FPD shift, the acuteness of FPD data sets increases. This fact should be considered in the process of deriving standard raw cow milk FPD limits. Similar experimental analysis of milk FPD technological shifts has not been performed in this way until now.
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Milaneze, H. S., L. S. Silva, L. B. M. Kottwitz, M. A. Zambom, L. M. Fonseca, A. T. B. Guimarães e M. S. S. Pozza. "Microbiological, chemical, physical, and proteolytic activities of raw milk after thermal processing". Arquivo Brasileiro de Medicina Veterinária e Zootecnia 70, n. 5 (ottobre 2018): 1625–32. http://dx.doi.org/10.1590/1678-4162-9662.
Testo completoAbstract (sommario):
ABSTRACT The aim was to evaluate the microbiological, chemical- physical, and shelf-life quality of milk samples after pasteurization (HTST) for 10 days or ultra-high temperature (UHT) treatment for 120 days. Raw milk counts of mesophilic aerobic microorganisms, Staphylococcus spp. and thermotolerant coliforms before HTST and UHT processing were 6.73 and 7.77; 2.84 and 4.30, and 4.68 and 4.37log10, respectively. Pseudomonas spp. were found in raw milk samples. No presence of any other microorganisms studied was detected and no microbial inhibitor was found. Processed samples met microbiological legal requirements. However, aerobic mesophilic counts for HTST pasteurized milk samples stored for 5 and 10 days increased to values comparable to those in raw milk. Composition chemical- physical of all samples were within legal limits. These results demonstrate that, although HTST and UHT processed milk comply with the microbiological standards required by Brazilian law, high microbial counts in raw milk are an issue, possibly due to failures in the early stages of the production chain. Increase in casein macropeptide (CMP), probably because of proteases psychrotrophic bacteria. It is concluded that the quality of raw milk directly influences the progressive increase of the CMP values.
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Kleinjan, Marije, Martijn JC van Herwijnen, Sten FWM Libregts, RJ Joost van Neerven, Anouk L. Feitsma e Marca HM Wauben. "Regular Industrial Processing of Bovine Milk Impacts the Integrity and Molecular Composition of Extracellular Vesicles". Journal of Nutrition 151, n. 6 (25 marzo 2021): 1416–25. http://dx.doi.org/10.1093/jn/nxab031.
Testo completoAbstract (sommario):
Abstract Background Bovine milk contains extracellular vesicles (EVs), which act as mediators of intercellular communication by regulating the recipients’ cellular processes via their selectively incorporated bioactive molecules. Because some of these EV components are evolutionarily conserved, EVs present in commercial milk might have the potential to regulate cellular processes in human consumers. Objectives Because commercial milk is subjected to industrial processing, we investigated its effect on the number and integrity of isolated milk EVs and their bioactive components. For this, we compared EVs isolated from raw bovine milk with EVs isolated from different types of commercial milk, including pasteurized milk, either homogenized or not, and ultra heat treated (UHT) milk. Methods EVs were separated from other milk components by differential centrifugation, followed by density gradient ultracentrifugation. EVs from different milk types were compared by single-particle high-resolution fluorescence-based flow cytometry to determine EV numbers, Cryo-electron microscopy to visualize EV integrity and morphology, western blot analysis to investigate EV-associated protein cargo, and RNA analysis to assess total small RNA concentration and milk-EV-specific microRNA expression. Results In UHT milk, we could not detect intact EVs. Interestingly, although pasteurization (irrespective of homogenization) did not affect mean ± SD EV numbers (3.4 × 108 ± 1.2 × 108–2.8 × 108 ± 0.3 × 107 compared with 3.1 × 108 ± 1.2 × 108 in raw milk), it affected EV integrity and appearance, altered their protein signature, and resulted in a loss of milk-EV-associated RNAs (from 40.2 ± 3.4 ng/μL in raw milk to 17.7 ± 5.4–23.3 ± 10.0 mg/μL in processed milk, P < 0.05). Conclusions Commercial milk, that has been heated by either pasteurization or UHT, contains fewer or no intact EVs, respectively. Although most EVs seemed resistant to pasteurization based on particle numbers, their integrity was affected and their molecular composition was altered. Thus, the possible transfer of bioactive components via bovine milk EVs to human consumers is likely diminished or altered in heat-treated commercial milk.
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Grant, Irene R., Edward I. Hitchings, Alan McCartney, Fiona Ferguson e Michael T. Rowe. "Effect of Commercial-Scale High-Temperature, Short-Time Pasteurization on the Viability of Mycobacterium paratuberculosis in Naturally Infected Cows' Milk". Applied and Environmental Microbiology 68, n. 2 (febbraio 2002): 602–7. http://dx.doi.org/10.1128/aem.68.2.602-607.2002.
Testo completoAbstract (sommario):
ABSTRACT Raw cows' milk naturally infected with Mycobacterium paratuberculosis was pasteurized with an APV HXP commercial-scale pasteurizer (capacity 2,000 liters/h) on 12 separate occasions. On each processing occasion, milk was subjected to four different pasteurization treatments, viz., 73�C for 15 s or 25 s with and without prior homogenization (2,500 lb/in2 in two stages), in an APV Manton Gaulin KF6 homogenizer. Raw and pasteurized milk samples were tested for M. paratuberculosis by immunomagnetic separation (IMS)-PCR (to detect the presence of bacteria) and culture after decontamination with 0.75% (wt/vol) cetylpyridinium chloride for 5 h (to confirm bacterial viability). On 10 of the 12 processing occasions, M. paratuberculosis was detectable by IMS-PCR, culture, or both in either raw or pasteurized milk. Overall, viable M. paratuberculosis was cultured from 4 (6.7%) of 60 raw and 10 (6.9%) of 144 pasteurized milk samples. On one processing day, in particular, M. paratuberculosis appeared to have been present in greater abundance in the source raw milk (evidenced by more culture positives and stronger PCR signals), and on this occasion, surviving M. paratuberculosis bacteria were isolated from milk processed by all four heat treatments, i.e., 73�C for 15 and 25 s with and without prior homogenization. On one other occasion, surviving M. paratuberculosis bacteria were isolated from an unhomogenized milk sample that had been heat treated at 73�C for 25 s. Results suggested that homogenization increases the lethality of subsequent heat treatment to some extent with respect to M. paratuberculosis, but the extended 25-s holding time at 73�C was found to be no more effective at killing M. paratuberculosis than the standard 15-s holding time. This study provides clear evidence that M. paratuberculosis bacteria in naturally infected milk are capable of surviving commercial high-temperature, short-time pasteurization if they are present in raw milk in sufficient numbers.
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Ruvalcaba-Gómez, José Martín, Héctor Ruiz-Espinosa, María Dolores Méndez-Robles, Ramón Ignacio Arteaga-Garibay, Luis Miguel Anaya-Esparza, Zuamí Villagrán e Raúl Jacobo Delgado-Macuil. "Use of Autochthonous Lactic Acid Bacteria as Starter Culture of Pasteurized Milk Adobera Cheese". Fermentation 8, n. 5 (18 maggio 2022): 234. http://dx.doi.org/10.3390/fermentation8050234.
Testo completoAbstract (sommario):
Adobera, a genuine, brick-shaped, lightly ripened, unstretched pasta filata-like cheese from Western México, is one of the most important market-share wise but is usually made with raw milk and prepared following artisanal procedures. A pasteurized milk cheese is needed to assess its safety and guarantee standardized quality features. However, no commercial Adobera cheese culture is available, as specific lactic acid bacteria relevant for its production have not been thoroughly identified. This study is aimed at comparing the technological and quality features of Adobera cheeses made with pasteurized milk inoculated with a mixture of autochthonous lactic acid bacteria (Lactobacillus and Leuconostoc strains) to those of traditional raw milk cheeses, hypothesizing that no significant differences would be found between them. Milk pasteurization promoted water retention into the cheese matrix, impacting its texture and color profiles. Raw milk cheeses were harder, more cohesive, and less elastic than pasteurized milk cheeses. Ripening markers were significantly higher in raw milk cheeses at all sampling times, although its evolution over time showed that the starter culture could exhibit similar proteolytic activity than that of native milk microbiota under favorable ripening conditions. The principal component analysis revealed apparent overall differences between raw Adobera cheeses and those made with pasteurized cheese milk.
35
Kažimírová, Viera. "Heat Consumption and Quality of Milk Pasteurization". Acta Technologica Agriculturae 16, n. 2 (1 giugno 2013): 55–58. http://dx.doi.org/10.2478/ata-2013-0014.
Testo completoAbstract (sommario):
Abstract This paper deals with milk processing with emphasis on pasteurization. The heat treatment of milk is important in terms of product quality and health safety. The goal of this paper is determination of heat consumption, inactivation effect and Pasteur criterion, by which pasteurization effectiveness is evaluated. The methodical part contains calculations, which were used for estimation of results and description of a pasteurization station used for milk processing. Results obtained in usual working time confirmed that necessary heating and cooling performance were achieved for guarantee of high-quality milk production. Real specific heat consumption was 51.69 kJ/kg. It was achieved by use of regeneration sections in the pasteurizer. These sections allow for a repeated use of 82 % of heat used for heating of raw milk in pasteurization.
36
HEUVELINK, A. E., B. BLEUMINK, F. L. A. M. van den BIGGELAAR, M. C. TE GIFFEL, R. R. BEUMER e E. de BOER. "Occurrence and Survival of Verocytotoxin-Producing Escherichia coli O157 in Raw Cow's Milk in the Netherlands". Journal of Food Protection 61, n. 12 (1 dicembre 1998): 1597–601. http://dx.doi.org/10.4315/0362-028x-61.12.1597.
Testo completoAbstract (sommario):
From May through November 1997, 1,011 samples of raw milk ffom bulk storage tanks were examined for the presence of verocytotoxin-producing Escherichia coli of serogroup O157 (O157 VTEC) by immunomagnetic separation following selective enrichment. The samples originated from 1,011 different dairy herds located throughout the Netherlands. O157 VTEC was not isolated from any of the milk samples examined. Additionally, survival of O157 VTEC in raw and UHT-sterilized cow's milk at 7 and 15°C was studied, both in the absence and presence of an activated lactoperoxidase-thiocyanate-hydrogen peroxide system (LPS). Results indicated that the O157 VTEC strain tested was able to grow in raw milk at 7°C as well as at 15°C. Naturally occurring amounts of thiocyanate and hydrogen peroxide in the raw milk tested were not sufficient to activate the LPS. Although the LPS exhibited an antimicrobial activity against O157 VTEC in LPS-activated sterilized milk, O157 VTEC populations were not (or not as obviously) reduced in LPS-activated raw milk. Possibly background microflora were more sensitive to the LPS than the O157 VTEC test strain. It was concluded that raw milk contaminated with O157 VTEC will remain a hazard if kept at 7 or 15°C. Effective pasteurization and avoiding postpasteurization contamination are necessary to ensure the safety of milk.
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Syed Malik, Nurfarhana, Mohd Nizam Lani e Fauziah Tufail Ahmad. "Stability of lactic acid bacteria and physico-chemical properties of pasteurized cow’s and goat’s milk". Malaysian Journal of Fundamental and Applied Sciences 15, n. 2-1 (15 maggio 2019): 341–45. http://dx.doi.org/10.11113/mjfas.v15n2-1.1560.
Testo completoAbstract (sommario):
This study was done to determine the effect of pasteurization on the stability of lactic acid bacteria and its enzyme, and also its relation with physico-chemical properties in raw and pasteurized cow’s and goat’s milk. Most of the physico-chemical properties (pH, protein, ash and fat) were highest in pasteurized goat’s milk. The total viable count for plate count of the bacterial concentration was higher in both pasteurized cow’s and goat’s milk which were 2.48 log CFU/ml. This was followed by raw cow’s milk (1.59 log CFU/ml) and raw goat’s milk (0.65 log CFU/ml). There was no yeast and mould detected in both raw and pasteurized cow’s and goat’s milk, respectively. Lactic acid bacteria (LAB) was found significantly higher in raw milk compared to pasteurized milk and higher macronutrients (proximate composition) could be considered as one of the factors for the survival of LAB. Interestingly, based on API ZYM assay kit result, there were nine different enzymes were detected in all samples which were leucine arylamidase, valine arylamidase, cystine arylamidase, trypsin, α-chymotrypsin, naphthol-AS-BI-phosphohydrolase, α-glucosidase, β-glucosidase and acid phosphatise. This result revealed that different types of lactic acid bacteria were detected in treated and non-treated milk samples produced by different animals.
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Efimova, E., L. Bahdanava, E. Dmitruk e S. Virina. "STUDY OF THE INFLUENCE OF TECHNOLOGICAL FACTORS IN THE PRODUCTION OF DAIRY PRODUCTS ON THE STABILITY OF ACYLTRANSFERASE ACTION". Topical issues of processing of meat and milk raw materials, n. 15 (21 dicembre 2021): 127–35. http://dx.doi.org/10.47612/2220-8755-2020-15-127-135.
Testo completoAbstract (sommario):
The article presents the results of research on the influence of technological factors on the stability of acyltransferase action. It is established that in the production of a product using cottage cheese technology, both by acidic and acid-rennet coagulation, pasteurization of raw milk is advisable at (76±1)°C and it is impractical to increase it to (90±1) ° C. It is determined that transglutaminase exhibits stability of action when used as a raw material not only cow's milk, but also sheep's and goat's milk.
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Wang, Cunfang, Xinman Lou e Jianmin Wang. "Fatty Acid Composition and Fat Stability of Raw Milk and Pasteurized Milk from Laoshan Goats". Journal of Agricultural Science 8, n. 6 (10 maggio 2016): 149. http://dx.doi.org/10.5539/jas.v8n6p149.
Testo completoAbstract (sommario):
<p>In this study, the fatty acid profile and fat stability for seven consecutive days of raw milk and pasteurized milk from Laoshan goats have been evaluated by gas chromatography-mass spectrometry (GC-MS) after fatty acid methyl ester. The results showed that the concentrations of short chain fatty acids (SCFA) and saturated fatty acids (SFA) significantly increased by 47.36% and 11.68% after pasteurization respectively, while the concentrations of unsaturated fatty acids (UFA), monounsaturated fatty acids (MUFA) and polyunsaturated fatty acids (PUFA) decreased by 26.08%, 26.45% and 22.15% respectively. The C10:0 (5.39%-8.57%), C12:0 (3.13%-5.28%), C14:0 (8.12%-11.87%), C16:0 (25.59%-28.53%), C18:0 (14.60-13.69%) and C18:1 (33.91-24.92%) are the most predominant fatty acids of Laoshan goat milk with significant differences. Moreover, the fat stabillity for seven consecutive days of raw milk and pasteurized milk was detected by sedimentation rate (R). The fat stability in pasteurized milk was more stable than that in raw milk, the sedimentation rate of raw milk and pasteurized milk consisted in a progressive decrease in the seven days by 82.99% and 79.77% respectively. What’s more, significant difference was observed from 1st day to 4th day between raw milk and pasteurized milk, however, there was no significance from 5th to 7th. This is the first report to fully characterize the fatty acid contents and fat stability of Laoshan goat raw milk and its pasteurized milk and it provided a certain theoretical basis for the research and development of goat milk functional product.</p>
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Lima, Hope K., Kenneth Vogel, Daniela Hampel, Montana Wagner-Gillespie e April D. Fogleman. "The Associations Between Light Exposure During Pumping and Holder Pasteurization and the Macronutrient and Vitamin Concentrations in Human Milk". Journal of Human Lactation 36, n. 2 (15 aprile 2020): 254–63. http://dx.doi.org/10.1177/0890334420906828.
Testo completoAbstract (sommario):
Background During pumping, storage, and pasteurization human milk is exposed to light, which could affect the concentrations of light-sensitive vitamins. Currently, milk banks do not regulate light exposure. Research Aim The aim of this paper was to determine the influence of light exposure during pumping, storage, and pasteurization on (1) macronutrients, (2) select water-soluble vitamins, and (3) select fat-soluble vitamins. Methods All 13 participants donated 4 milk samples each. Each sample underwent 1 of 4 treatments: raw and light protected, raw and light exposed, pasteurized and light protected, and pasteurized and light exposed. Samples were analyzed for macronutrients and Vitamins B1, B2, retinol, γ-tocopherol, α-tocopherol, and β-carotene. Results β-carotene concentrations were not influenced by light exposure. Vitamin B1 was significantly ( p < 0.05) affected by light-exposure ( M = 0.23, SD = 0.01mg/L) compared to light-protected ( M = 0.27, SD = 0.01mg/L) samples. Vitamin B2 concentrations were reduced ( p < 0.05) by light-exposure in raw ( M = 62.1, SD = 0.61µg/L) and pasteurized ( M = 73.7, SD = 0.72µg/L) samples compared to light-protected raw samples ( M = 99.7, SD = 0.66µg/L). No other tested nutrients were affected by light exposure. Conclusions If milk is exposed to excessive amounts of light, Vitamins B1 and B2 concentrations may degrade below the current Adequate Intake recommendations for infants 0–6 months of age, increasing the risk of insufficient vitamin supply to the exclusively human milk-fed infant. Thus, pumped or processed human milk should be protected from light to preserve milk vitamin concentrations.
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Afrin, Nazia, SM Rokon Ud Doula e Rasheda Yasmin Shilpi. "Detection of pathogenic bacteria from raw, pasteurized and UHT milk available in the local market of Gazipur District". Jahangirnagar University Journal of Biological Sciences 7, n. 2 (30 dicembre 2018): 13–19. http://dx.doi.org/10.3329/jujbs.v7i2.40743.
Testo completoAbstract (sommario):
The present study was undertaken with the aim of investigating the bacteriological quality of locally available raw, pasteurized and UHT milk in Gazipur District. A total 5 raw, pasteurized and UHT milk samples were collected during November to December 2016. All the pasteurized and UHT milk samples showed the total aerobic heterotrophic bacterial (TAHB) level above the standard acceptable range (i.e. > 104 cfu/ml for pasteurized milk and > 0 for UHT milk). Both Gram positive and Gram negative pathogenic bacteria viz. Staphylococcus aureus, S. epidermidis, Bacillus sp., Pseudomonas sp. and Enterobacter sp. were isolated from studied samples. API 20 E was used for confirmation of Pseudomonas sp. This study indicates that most of the pasteurized and UHT milk samples were not satisfactory in terms of public health standard. Therefore, care must be taken to avoid possible health risk in every step involving collection, transportation, storage and post pasteurization handing of raw milk.
Jahangirnagar University J. Biol. Sci. 7(2): 13-19, 2018 (December)
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Sviridenko, G. M., T. V. Komarova e E. E. Uskova. "Study of the composition of the residual microflora of milk after pasteurization". Food systems 5, n. 4 (9 gennaio 2023): 344–52. http://dx.doi.org/10.21323/2618-9771-2022-5-4-344-352.
Testo completoAbstract (sommario):
The article presents the results of studies of the composition of the residual microflora of pasteurized milk, depending on the bacterial landscape and the initial contamination of raw milk. The thermal stability of test cultures of microorganisms that significantly affect the quality and storage capacity of fermented dairy products has been studied. To study the composition of the residual microflora of milk after pasteurization, sterile milk was infected with test cultures of microorganisms at doses from 101 CFU/cm3 to 107 CFU/cm3. After infection, the milk was pasteurized at temperatures of (72 ± 1) °C and (80 ± 1) °C with a holding time of 10–20 seconds. The detection and enumeration of microorganisms was carried out by standardized microbiological methods. Microorganisms were identified by visual assessment of dominant colonies and cell morphology in micropreparations. The thermal stability of microorganisms important for dairy products, in particular cheeses, the source of which is raw milk, has been studied. It has been established that of the coccal forms, the greatest risks are associated with enterococci. Escherichia coli at infection doses above 106 CFU/cm3 partially retains viability both at low-temperature and at high-temperature pasteurization. Pasteurization temperatures do not have a lethal effect on spore bacilli, their number in pasteurized milk does not decrease, regardless of the initial dose of infection. Low-temperature pasteurization activates the process of clostridial spore germination. The ability to reactivate cells after thermal shock was observed in Escherichia coli, Staphylococcus aureus, Pseudomonas, and mold fungi. Thus, the residual microflora of milk subjected to low-temperature pasteurization is represented by enterococci, thermophilic streptococci, micrococci, staphylococci, asporogenous bacilli and spore bacteria. The above microorganisms constitute the residual microflora of pasteurized milk and are involved in the maturation of cheeses, determining their quality and safety, [as well as] affecting the storage capacity of the finished product.
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Weingart, Oliver G., Tanja Schreiber, Conny Mascher, Diana Pauly, Martin B. Dorner, Thomas F. H. Berger, Charlotte Egger et al. "The Case of Botulinum Toxin in Milk: Experimental Data". Applied and Environmental Microbiology 76, n. 10 (2 aprile 2010): 3293–300. http://dx.doi.org/10.1128/aem.02937-09.
Testo completoAbstract (sommario):
ABSTRACT Botulinum neurotoxin (BoNT) is the most toxic substance known to man and the causative agent of botulism. Due to its high toxicity and the availability of the producing organism Clostridium botulinum, BoNT is regarded as a potential biological warfare agent. Because of the mild pasteurization process, as well as rapid product distribution and consumption, the milk supply chain has long been considered a potential target of a bioterrorist attack. Since, to our knowledge, no empirical data on the inactivation of BoNT in milk during pasteurization are available at this time, we investigated the activities of BoNT type A (BoNT/A) and BoNT/B, as well as their respective complexes, during a laboratory-scale pasteurization process. When we monitored milk alkaline phosphatase activity, which is an industry-accepted parameter of successfully completed pasteurization, our method proved comparable to the industrial process. After heating raw milk spiked with a set amount of BoNT/A or BoNT/B or one of their respective complexes, the structural integrity of the toxin was determined by enzyme-linked immunosorbent assay (ELISA) and its functional activity by mouse bioassay. We demonstrated that standard pasteurization at 72°C for 15 s inactivates at least 99.99% of BoNT/A and BoNT/B and at least 99.5% of their respective complexes. Our results suggest that if BoNTs or their complexes were deliberately released into the milk supply chain, standard pasteurization conditions would reduce their activity much more dramatically than originally anticipated and thus lower the threat level of the widely discussed “BoNT in milk” scenario.
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Zavgorodniy, A. I., A. P. Paliy, B. T. Stegniy e S. K. Gorbatenko. "Infrared milk pasterizer as a component of success in the Animal leukemia control". Journal for Veterinary Medicine, Biotechnology and Biosafety 5, n. 3 (16 settembre 2019): 5–9. http://dx.doi.org/10.36016/jvmbbs-2019-5-3-1.
Testo completoAbstract (sommario):
One of the most common and dangerous cattle diseases of oncogenic origin is leukemia. An effective technological step to control animal leukemia and to prevent the possibility of its further spread is milk pasteurization. We have studied the quality of dairy raw materials and equipment used in the pasteurization of milk. The resistance of pasteurized milk was compared after using various methods of its processing (storage in a refrigerator at a temperature of 4–5°C). The comparative characteristics and specific energy consumption of the most popular pasteurizer models with ‘UOM’ milk pasteurizer-disinfectant were described. We studied the specific energy consumption of the ‘UOM’ units. It was established that pasteurization of milk in cattle leukemia is an integral stage in the overall complex of veterinary and sanitary measures. For pasteurization in livestock farms and milk processing plants, it is necessary to install modern, energy-saving, highly efficient pasteurizers using infrared heating. When using infrared equipment for pasteurization-disinfection of milk (‘UOM’), the disinfection of milk occurs at 79.5°C in a stream (without exposure). This mode of milk processing completely destroys the leukemia virus in it and does not affect its nutritional qualities
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Papademas, Photis, Panagiotis Mousikos e Maria Aspri. "Optimization of UV-C Processing of Donkey Milk: An Alternative to Pasteurization?" Animals 11, n. 1 (28 dicembre 2020): 42. http://dx.doi.org/10.3390/ani11010042.
Testo completoAbstract (sommario):
The effect of UV-C light technology on the inactivation of six foodborne pathogens inoculated in raw donkey milk was evaluated. Fresh raw donkey milk was artificially inoculated with the following foodborne pathogens—L. inoccua (NCTC 11288), S. aureus (NCTC 6571), B. cereus (NCTC 7464), Cronobacter sakazakii (NCTC 11467), E. coli (NCTC 9001), Salmonella enteritidis (NCTC 6676)—and then treated with UV-C doses of up to 1300 J/L. L. innocua was the most UV-C-resistant of the bacteria tested, requiring 1100 J/L for complete inactivation, while the rest of the bacteria tested was destructed in the range of 200–600 J/L. Results obtained from this study indicate that UV-C light technology has the potential to be used as a non-thermal processing method for the reduction of spoilage bacteria and foodborne pathogens that can be present in raw donkey milk.
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Rimsha, Rimsha, Javeria Munir, Ishrat Fatima, Naba Ishfaq, Haiqa Shahid, Haneeza Murtaza e Khursheed Haroon. "Safety and Quality Assessment of Milk Before and After Pasteurization Collected from Different Regions of Punjab". Scholars International Journal of Chemistry and Material Sciences 5, n. 9 (5 novembre 2022): 135–50. http://dx.doi.org/10.36348/sijcms.2022.v05i09.001.
Testo completoAbstract (sommario):
Milk is an excellent source of proteins, fats and carbohydrates along with minerals and vitamins. It is the balanced diet for all age groups. In Pakistan consumption of milk is increasing day by day. Milk from different animal sources has quality and nutritional differences. Pasteurization found to be increased the milk quality and shelf-life stability by reducing microbial load. The objective of study is to evaluate the differences among the raw and pasteurized milk in terms of safety and microbial distribution. The proximate and quality analysis including moisture, crude protein, crude fat, total soluble solid, pH, acidity, lactose composition, solid-not-fat (SNF) and specific gravity were done for the milk samples. The microbial tests were performed for Total Plate Count and Total Coliform Count before and after pasteurization process. The collected data was analysed statistically to estimate the level of significance. Pasteurized milk of buffalo showed high value for pH 6.65, lactose composition 5.964, crude fat 7.974%, crude protein 6.453%, SNF 6.672%, Total solids 12.646% while pasteurized cow milk showed low value as compare to buffalo milk samples as pH 6.60, lactose composition 4.732, crude fat 4.744%, crude protein 4.353%, SNF 6.128%, Total solids 10.872%. Total Coliform count (TCC) for raw and pasteurized milk of cow was 3.320 CFU/ml and 1.2600 CFU/ml respectively, whereas for buffaloes it was 2.604 CFU/ml and 1.0900 CFU/ml respectively. In case of TPC it was 2.834CFU/ml and 1.132 CFU/ml for raw to pasteurized milk of cow while it was 2.0320 CFU/ml and 1.0720 CFU/ml in buffaloes. Result revealed that pasteurized milk is safer to use and pasteurized milk has low microbial count as well as authenticity in safety and quality when compared with unpasteurized milk.
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Granger-Delacroix, Manon, Nadine Leconte, Fabienne Garnier-Lambrouin, Françoise Le Goff, Marieke Van Audenhaege e Geneviève Gésan-Guiziou. "Transmembrane Pressure and Recovery of Serum Proteins during Microfiltration of Skimmed Milk Subjected to Different Storage and Treatment Conditions". Foods 9, n. 4 (27 marzo 2020): 390. http://dx.doi.org/10.3390/foods9040390.
Testo completoAbstract (sommario):
Milk pre-processing steps-storage at 4 °C (with durations of 48, 72 or 96 h) and methods for microbiological stabilization of milk (1.4 μm microfiltration, thermization, thermization + bactofugation, pasteurization) are performed industrially before 0.1 µm-microfiltration (MF) of skimmed milk to ensure the microbiological quality of final fractions. The objective of this study was to better understand the influence of these pre-processing steps and their cumulative effects on MF performances (i.e., transmembrane pressure, and transmission and recovery of serum proteins (SP) in the permeate). Results showed that heat treatment of skimmed milk decreased ceramic MF performances, especially after a long 4 °C storage duration (96 h) of raw milk: when milk was heat treated by pasteurization after 96 h of storage at 4 °C, the transmembrane pressure increased by 25% over a MF run of 330 min with a permeation flux of 75 L·h−1·m−2 and a volume reduction ratio of 3.0. After 48 h of storage at 4 °C, all other operating conditions being similar, the transmembrane pressure increased by only 6%. When milk was 1.4 µm microfiltered, the transmembrane pressure also increased by only 6%, regardless of the duration of 4 °C storage. The choice of microbiological stabilization method also influenced SP transmission and recovery: the higher the initial heat treatment of milk, the lower the transmission of SP and the lower their recovery in permeate. Moreover, the decline of SP transmission was all the higher that 4 °C storage of raw milk was long. These results were explained by MF membrane fouling, which depends on the load of microorganisms in the skimmed milks to be microfiltered as well as the rate of SP denaturation and/or aggregation resulting from pre-processing steps.
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Ribeiro Junior, Jose Carlos, Vanerli Beloti, Fernanda Pelisson Massi e Maria Helena Pelegrinelli Fungaro. "Thermoduric psychrotrophic proteolytic microbiota from refrigerated raw milk". Semina: Ciências Agrárias 38, n. 1 (2 marzo 2017): 267. http://dx.doi.org/10.5433/1679-0359.2017v38n1p267.
Testo completoAbstract (sommario):
Thermoduric microorganisms may withstand high temperatures during the pasteurization of milk. Therefore, the microbiota in pasteurized milk consist of thermoduric microbes and directly influence the shelf-life of the milk. The aim of this study was to identify thermoduric psychrotrophic proteolytic microbiota in refrigerated raw milk. Twenty samples, previously heat-treated, were streaked and incubated at 7°C for 10 days. The strains isolated were streaked on milk agar to assess proteolytic activity and were initially analyzed morphologically by light microscopy and then by molecular techniques to identify the species. In 40% of the samples analyzed was observed only one bacterial growth and others 10 thermoduric psychrotrophic fungi. All isolates were proteolytic. The sequencing of 16S rRNA gene identified the bacterial strain as Bacillus pumilus and analysis of the ITS1-5.8S-ITS2 region of fungal isolates revealed the Cladosporium cladosporioides (60%), Curvularia geniculatus (10%), and the 3 remaining strains were identified as Geotrichum candidum (30%). This is a fist description of B. pumilus in Brazilian raw milk. Considering the spoilage potential of all isolates and of the fungi present in raw milk and their survival in pasteurized milk, it is extremely important to carry out further studies to your resistant to heat, their impact on the shelf-life of pasteurized milk, ultra-high temperature (UHT) milk and dairy products.
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McDonald, Wendy L., Kimberly J. O'Riley, Christopher J. Schroen e Robin J. Condron. "Heat Inactivation of Mycobacterium avium subsp. paratuberculosis in Milk". Applied and Environmental Microbiology 71, n. 4 (aprile 2005): 1785–89. http://dx.doi.org/10.1128/aem.71.4.1785-1789.2005.
Testo completoAbstract (sommario):
ABSTRACT The effectiveness of pasteurization and the concentration of Mycobacterium avium subsp. paratuberculosis in raw milk have been identified in quantitative risk analysis as the most critical factors influencing the potential presence of viable Mycobacterium paratuberculosis in dairy products. A quantitative assessment of the lethality of pasteurization was undertaken using an industrial pasteurizer designed for research purposes with a validated Reynolds number of 62,112 and flow rates of 3,000 liters/h. M. paratuberculosis was artificially added to raw whole milk, which was then homogenized, pasteurized, and cultured, using a sensitive technique capable of detecting one organism per 10 ml of milk. Twenty batches of milk containing 103 to 104 organisms/ml were processed with combinations of three temperatures of 72, 75, and 78°C and three time intervals of 15, 20, and 25 s. Thirty 50-ml milk samples from each processed batch were cultured, and the logarithmic reduction in M. paratuberculosis organisms was determined. In 17 of the 20 runs, no viable M. paratuberculosis organisms were detected, which represented >6-log10 reductions during pasteurization. These experiments were conducted with very heavily artificially contaminated milk to facilitate the measurement of the logarithmic reduction. In three of the 20 runs of milk, pasteurized at 72°C for 15 s, 75°C for 25 s, and 78°C for 15 s, a few viable organisms (0.002 to 0.004 CFU/ml) were detected. Pasteurization at all temperatures and holding times was found to be very effective in killing M. paratuberculosis, resulting in a reduction of >6 log10 in 85% of runs and >4 log10 in 14% of runs.
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SARVER, RONALD, CAYLEY HIGBEE, PREETHA BISWAS, LEI ZHANG, NATE BANNER, JENNIFER RICE, MARK MOZOLA et al. "A Portable Chemiluminescence Assay of Alkaline Phosphatase Activity to Monitor Pasteurization of Milk Products". Journal of Food Protection 82, n. 12 (15 novembre 2019): 2119–25. http://dx.doi.org/10.4315/0362-028x.jfp-19-153.
Testo completoAbstract (sommario):
ABSTRACT A chemiluminescence assay using a handheld luminometer to measure the activity of alkaline phosphatase was developed that can detect 0.002% or more of unpasteurized milk in various milk products. Evaluation of the assay followed an National Conference on Interstate Milk Shipments (NCIMS)–approved protocol in which aliquots of pasteurized milk products were spiked with raw milk at various levels. Milk products evaluated included skim white milk, 1 and 2% fat content white milk, whole white milk, strawberry-flavored 1% fat content milk, chocolate-flavored 1% fat content milk, half-and-half, and heavy cream. Split samples were prepared, and alkaline phosphatase activities were determined in triplicate on 4 days by three NCIMS-accredited laboratories by the chemiluminescent method and NCIMS-approved reference methods. Equivalence of the chemiluminescent method to the approved reference methods was demonstrated for all eight products evaluated over a range of raw milk concentration from 0 to 0.5%, using criteria established by NCIMS, in which mean results obtained by the three laboratories by the chemiluminescent method were within 1 standard deviation of the mean results obtained by the NCIMS-approved reference methods at each alkaline phosphatase concentration. Procedures for measurement of microbial and reactivated alkaline phosphatase were also established for the method. HIGHLIGHTS