To see the other types of publications on this topic, follow the link: Tomatoes Tomatoes Lettuce Lettuce.
Journal articles on the topic 'Tomatoes Tomatoes Lettuce Lettuce'
Create a spot-on reference in APA, MLA, Chicago, Harvard, and other styles
Consult the top 50 journal articles for your research on the topic 'Tomatoes Tomatoes Lettuce Lettuce.'
Next to every source in the list of references, there is an 'Add to bibliography' button. Press on it, and we will generate automatically the bibliographic reference to the chosen work in the citation style you need: APA, MLA, Harvard, Chicago, Vancouver, etc.
You can also download the full text of the academic publication as pdf and read online its abstract whenever available in the metadata.
Browse journal articles on a wide variety of disciplines and organise your bibliography correctly.
1
GUPTA, S. K., K. NALLUSWAMI, C. SNIDER, M. PERCH, M. BALASEGARAM, D. BURMEISTER, J. LOCKETT, C. SANDT, R. M. HOEKSTRA, and S. MONTGOMERY. "Outbreak ofSalmonellaBraenderup infections associated with Roma tomatoes, northeastern United States, 2004: a useful method for subtyping exposures in field investigations." Epidemiology and Infection 135, no. 7 (February 5, 2007): 1165–73. http://dx.doi.org/10.1017/s0950268807007911.
Full textAbstract:
SUMMARYSalmonellaBraenderup is an uncommon serotype in the United States. In July 2004, a multistate outbreak ofSalmonellaBraenderup diarrhoeal infections occurred, with 125 clinical isolates identified. To investigate, we conducted a case-control study, enrolling 32 cases and 63 matched controls. Cheese, lettuce and tomato eaten at restaurants all appeared to be associated with illness. To further define specific exposures, we conducted a second study and asked managers of restaurants patronized by patients and controls about cheese, lettuce and tomato varieties used in dishes their patrons reported consuming. This information was obtained for 27 cases and 29 controls. Roma tomatoes were the only exposure significantly associated with illness (odds ratio 4·3, 95% confidence interval 1·2–15·9). Roma tomatoes from two restaurants were traced back to a single tomato packing house. The methods used in this field investigation to define specific exposures may be useful for other foodborne outbreaks.
2
Hertrich, Sarah M., Glenn Boyd, Joseph Sites, and Brendan A. Niemira. "Cold Plasma Inactivation of Salmonella in Prepackaged, Mixed Salads Is Influenced by Cross-Contamination Sequence." Journal of Food Protection 80, no. 12 (November 1, 2017): 2132–36. http://dx.doi.org/10.4315/0362-028x.jfp-17-242.
Full textAbstract:
ABSTRACT Customer demand for convenient food products has led to an increased production of prepackaged and ready-to-eat food products. Most of these products rely mainly on surface disinfection and other traditional approaches to ensure shelf life and safety. Novel processing techniques, such as cold plasma, are currently being investigated to enhance the safety and shelf life of prepacked foods. The purpose of this study was to determine the effects of cold plasma corona discharge on the inactivation of Salmonella on prepackaged, tomato-and-lettuce mixed salads. Two different inoculation methods were evaluated to address cross-contamination of Salmonella from cherry tomatoes to lettuce and vice versa. In separate studies, a sample of either cherry tomatoes (55 g) or romaine lettuce (10 g) was inoculated with a Salmonella cocktail (6.93 ± 0.99 log CFU/mL), placed into a commercial polyethylene terephthalate plastic container, and thoroughly mixed together with its noninoculated counterpart. Mixed salads were allowed to dry in a biosafety cabinet for 1 h. Samples were treated with 35 kV cold plasma corona discharge inside plastic containers for 3 min. Samples were stomached and serially diluted in buffered peptone water and then were plated onto aerobic plate count Petrifilm and incubated for 18 h at 37°C. When lettuce was the inoculated counterpart, log kill of Salmonella was significantly greater on tomatoes (0.75 log CFU/g) compared with lettuce (0.34 log CFU/g) (P = 0.0001). Salmonella was reduced on mixed salad only when lettuce was the inoculated counterpart (0.29 log CFU/g) (P = 0.002). Cold plasma can kill Salmonella in a prepackaged mixed salad, with efficacy dependent on the nature of contamination, direction of transfer, and the surface topography of the contaminated commodity.
3
ARTHUR, LINDSAY, SANDRA JONES, MARTHA FABRI, and JOSEPH ODUMERU. "Microbial Survey of Selected Ontario-Grown Fresh Fruits and Vegetables." Journal of Food Protection 70, no. 12 (December 1, 2007): 2864–67. http://dx.doi.org/10.4315/0362-028x-70.12.2864.
Full textAbstract:
Recent produce-related outbreaks have been receiving heightened media coverage, which has increased public concern toward the safety of fresh fruits and vegetables. In response, the microbial contamination of Ontario-grown fresh fruits and vegetables was evaluated by the Ontario Ministry of Agriculture, Food and Rural Affairs during the summer of 2004. Prior to this survey, information specific to the microbial contamination of Ontario-produced fruits and vegetables was limited. This nonregulatory survey had two objectives: (i) to obtain a general microbiological profile of selected fruits and vegetables produced in Ontario and (ii) to use the information and knowledge gained from this survey to direct and support future on-farm food safety research and food safety programs to manage potential risks. In all, 1,183 samples, including muskmelon (151), scallions and green onions (173), leaf lettuce (263), organic leaf lettuce (112), head lettuce (155), parsley (127), cilantro (61), and fresh market tomatoes (141), were collected and analyzed. Samples were analyzed for Salmonella, Shigella, and generic E. coli. Enrichment cultures positive for E. coli were further assessed for verotoxigenicity. One sample each of Roma tomato and organic leaf lettuce were positive for Salmonella, with no samples yielding Shigella or verotoxigenic E. coli. The E. coli prevalence was highest in parsley (13.4%), followed by organic leaf lettuce (11.6%), leaf lettuce (6.5%), scallions (6.4%), cilantro (4.9%), muskmelon (1.3%), head lettuce (0%), and fresh market tomatoes (0%). These findings, in combination with foodborne illness data, will help target those commodities that require more focused risk mitigation efforts.
4
KILONZO-NTHENGE, AGNES, FUR-CHI CHEN, and SANDRIA L. GODWIN. "Efficacy of Home Washing Methods in Controlling Surface Microbial Contamination on Fresh Produce." Journal of Food Protection 69, no. 2 (February 1, 2006): 330–34. http://dx.doi.org/10.4315/0362-028x-69.2.330.
Full textAbstract:
Much effort has been focused on sanitation of fresh produce at the commercial level; however, few options are available to the consumer. The purpose of this study was to determine the efficacy of different cleaning methods in reducing bacterial contamination on fresh produce in a home setting. Lettuce, broccoli, apples, and tomatoes were inoculated with Listeria innocua and then subjected to combinations of the following cleaning procedures: (i) soak for 2 min in tap water, Veggie Wash solution, 5% vinegar solution, or 13% lemon solution and (ii) rinse under running tap water, rinse and rub under running tap water, brush under running tap water, or wipe with wet/dry paper towel. Presoaking in water before rinsing significantly reduced bacteria in apples, tomatoes, and lettuce, but not in broccoli. Wiping apples and tomatoes with wet or dry paper towel showed lower bacterial reductions compared with soaking and rinsing procedures. Blossom ends of apples were more contaminated than the surface after soaking and rinsing; similar results were observed between flower section and stem of broccoli. Reductions of L. innocua in both tomatoes and apples (2.01 to 2.89 log CFU/g) were more than in lettuce and broccoli (1.41 to 1.88 log CFU/g) when subjected to same washing procedures. Reductions of surface contamination of lettuce after soaking in lemon or vinegar solutions were not significantly different (P > 0.05) from lettuce soaking in cold tap water. Therefore, educators and extension workers might consider it appropriate to instruct consumers to rub or brush fresh produce under cold running tap water before consumption.
5
Obermeier, C., J. L. Sears, H. Y. Liu, K. O. Schlueter, E. J. Ryder, J. E. Duffus, S. T. Koike, and G. C. Wisler. "Characterization of Distinct Tombusviruses that Cause Diseases of Lettuce and Tomato in the Western United States." Phytopathology® 91, no. 8 (August 2001): 797–806. http://dx.doi.org/10.1094/phyto.2001.91.8.797.
Full textAbstract:
A soilborne disease of lettuce, associated with necrosis and dieback, has been found with increasing frequency in California and Arizona over the last 10 years. An isometric virus, serologically related to Tomato bushy stunt virus (TBSV), was consistently isolated from lettuce plants with these disease symptoms. Back-inoculation to healthy lettuce plants and subsequent reisolation of the virus from symptomatic lettuce leaves suggested that this virus was the causal agent of this disease. A tombusvirus was also associated with a necrosis disease of greenhouse-grown tomatoes in Colorado and New Mexico. Complementary DNA representing the 3′ end of viral genomic RNAs recovered from diseased lettuce and tomato plants had identical nucleotide sequences. However, these sequences were divergent (12.2 to 17.1%) from sequences of the previously described strains of TBSV, Petunia asteroid mosaic virus (PAMV), Artichoke mottled crinkle virus, and Carnation Italian ringspot virus. Additional tombusvirus isolates were recovered from diseased lettuce and tomato plants and these were most closely related to the TBSV-cherry strain (synonymous with PAMV) and to Cucumber necrosis virus based on comparison of 3′-end sequences (0.1 to 0.6% and 4.8 to 5.1% divergence, respectively). Western blot analysis revealed that the new tombusvirus isolated from diseased lettuce and tomato plants in the western United States is serologically distinct from previously described tombusvirus species and strains. Based on genomic and serological properties, we propose to classify this virus as a new tombusvirus species and name it Lettuce necrotic stunt virus.
6
SY, KAYE V., MELINDA B. MURRAY, M. DAVID HARRISON, and LARRY R. BEUCHAT. "Evaluation of Gaseous Chlorine Dioxide as a Sanitizer for Killing Salmonella, Escherichia coli O157:H7, Listeria monocytogenes, and Yeasts and Molds on Fresh and Fresh-Cut Produce." Journal of Food Protection 68, no. 6 (June 1, 2005): 1176–87. http://dx.doi.org/10.4315/0362-028x-68.6.1176.
Full textAbstract:
Gaseous chlorine dioxide (ClO2) was evaluated for effectiveness in killing Salmonella, Escherichia coli O157:H7, and Listeria monocytogenes on fresh-cut lettuce, cabbage, and carrot and Salmonella, yeasts, and molds on apples, peaches, tomatoes, and onions. Inoculum (100 μl, ca. 6.8 log CFU) containing five serotypes of Salmonella enterica, five strains of E. coli O157:H7, or five strains of L. monocytogenes was deposited on the skin and cut surfaces of fresh-cut vegetables, dried for 30 min at 22°C, held for 20 h at 4°C, and then incubated for 30 min at 22°C before treatment. The skin surfaces of apples, peaches, tomatoes, and onions were inoculated with 100 μl of a cell suspension (ca. 8.0 log CFU) containing five serotypes of Salmonella, and inoculated produce was allowed to dry for 20 to 22 h at 22°C before treatment. Treatment with ClO2 at 4.1 mg/liter significantly (α = 0.05) reduced the population of foodborne pathogens on all produce. Reductions resulting from this treatment were 3.13 to 4.42 log CFU/g for fresh-cut cabbage, 5.15 to 5.88 log CFU/g for fresh-cut carrots, 1.53 to 1.58 log CFU/g for fresh-cut lettuce, 4.21 log CFU per apple, 4.33 log CFU per tomato, 1.94 log CFU per onion, and 3.23 log CFU per peach. The highest reductions in yeast and mold populations resulting from the same treatment were 1.68 log CFU per apple and 2.65 log CFU per peach. Populations of yeasts and molds on tomatoes and onions were not significantly reduced by treatment with 4.1 mg/liter ClO2. Substantial reductions in populations of pathogens on apples, tomatoes, and onions but not peaches or fresh-cut cabbage, carrot, and lettuce were achieved by treatment with gaseous ClO2 without markedly adverse effects on sensory qualities.
7
McBride, M. B. "Arsenic and Lead Uptake by Vegetable Crops Grown on Historically Contaminated Orchard Soils." Applied and Environmental Soil Science 2013 (2013): 1–8. http://dx.doi.org/10.1155/2013/283472.
Full textAbstract:
Transfer of Pb and As into vegetables grown on orchard soils historically contaminated by Pb arsenate pesticides was measured in the greenhouse. Lettuce, carrots, green beans, and tomatoes were grown on soils containing a range of total Pb (16.5–915 mg/kg) and As (6.9–211 mg/kg) concentrations. The vegetables were acid-digested and analyzed for total Pb and As using ICP-mass spectrometry. Vegetable contamination was dependent on soil total Pb and As concentrations, pH, and vegetable species. Arsenic concentrations were the highest in lettuce and green beans, lower in carrots, and much lower in tomato fruit. Transfer of Pb into lettuce and beans was generally lower than that of As, and Pb and As were strongly excluded from tomato fruit. Soil metal concentrations as high as 400 mg/kg Pb and 100 mg/kg As produced vegetables with concentrations of Pb and As below the limits of international health standards.
8
ALBRECHT, JULIE A., FAYRENE L. HAMOUZ, SUSAN S. SUMNER, and VANESSA MELCH. "Microbial Evaluation of Vegetable Ingredients in Salad Bars†." Journal of Food Protection 58, no. 6 (June 1, 1995): 683–85. http://dx.doi.org/10.4315/0362-028x-58.6.683.
Full textAbstract:
Vegetable salad ingredients (lettuce, tomatoes, broccoli, and cauliflower) purchased from three grocery-store deli operations were analyzed for total plate count, coliforms, yeasts, and molds. The temperature of the vegetable ingredients was measured at the time of purchase and the pH was measured on all samples within one-half hour after purchase. In the second phase, fresh broccoli was processed into florets, inoculated with E. coli ATCC 23742, and subjected to three washing treatments. The temperature of the salad ingredients ranged from 5.1°C to 18.9°C. The pH ranges for the vegetables were broccoli, 5.46 to 6.39; cauliflower, 5.82 to 6.65; lettuce, 4.92 to 6.38; and tomatoes, 3.30 to 4.47. The total aerobic count for the vegetables ranged from 5.51 to 6.63 log CFU/g. Coliforms on the vegetables ranged from 4.89 to 6.30 log CFU/g. Yeasts and molds were found on all vegetables. The results of the study indicate that the temperature conditions and pH ranges for the broccoli, cauliflower, and lettuce could support microbial growth. The pH range of the tomatoes was below 4.6, but if contaminated and added to low acid foods, the tomatoes may also act as a vehicle for microbial contamination. When a chlorine wash solution was used, it slightly reduced the aerobic microbial load on previously inoculated broccoli and reduced the coliform population of the broccoli by approximately one log unit.
9
Abou-Jawdah, Y., C. El Mohtar, H. Sobh, and M. K. Nakhla. "First Report of Tomato spotted wilt virus on Tomatoes in Lebanon." Plant Disease 90, no. 3 (March 2006): 376. http://dx.doi.org/10.1094/pd-90-0376a.
Full textAbstract:
During the spring and summer of 2004, an epidemic of Tomato spotted wilt virus (TSWV) (genus Tospovirus, family Bunyaviridae) was observed in an isolated tomato field at an elevation of 1,000 m in Lebanon. Symptoms were characteristic of TSWV (2). Seedlings came from a nursery in the coastal area of Byblos. In the spring of 2005, TSWV-like symptoms (2) appeared on tomato in the same mountainous area, as well as on tomato, pepper, and lettuce crops in the Byblos coastal area. Initial diagnosis using TSWV ImmunoStrip Tests (Agdia, IN) gave positive results on tomato and lettuce samples. When these samples were analyzed using reverse transcription-polymerase chain reaction, a specific band (619 nt) was observed in symptomatic samples but not in healthy controls (1). Amplicons were cloned into the pGEM-T easy vector (Promega, Madison, WI) and three clones were sequenced in both directions (GenBank Accession No. DQ131804). Sequence analysis revealed more than 99% nucleotide identity (GenBank Accession Nos. AY744476, AJ297611, and AJ418781) and 99% amino acid identity and 100% amino acid similarity (GenBank Accession Nos. AAU95409, CAA85356, and CAD11452) to the nucleocapsid protein of several TSWV isolates. To our knowledge, this is the first report of TSWV in Lebanon. To prevent rapid spread, farmers were informed about the disease, its vector, and appropriate preventive control measures. References: (1) S. Adkins and E. N. Rosskopf. Plant Dis. 86:1310, 2002. (2) G. Marchoux et al. Plant Pathol. 40:347, 1991.
10
Poulik, Zdenek. "Influence of nickel contaminated soils on lettuce and tomatoes." Scientia Horticulturae 81, no. 3 (September 1999): 243–50. http://dx.doi.org/10.1016/s0304-4238(99)00023-0.
Full text
11
HESHMATI, ALI, FERESHTEH MEHRI, JAVAD KARAMI-MOMTAZ, and AMIN MOUSAVI KHANEGHAH. "Concentration and Risk Assessment of Potentially Toxic Elements, Lead and Cadmium, in Vegetables and Cereals Consumed in Western Iran." Journal of Food Protection 83, no. 1 (December 19, 2019): 101–7. http://dx.doi.org/10.4315/0362-028x.jfp-19-312.
Full textAbstract:
ABSTRACT The concentration of cadmium (Cd) and lead (Pb) in vegetable (potatoes, onions, tomatoes, lettuce, leeks, and carrots) and cereal (wheat and rice) samples collected from Iran were investigated by a graphite furnace atomic absorption spectrophotometer. In addition, we determined the health risks due to exposure to Cd and Pb through vegetable and cereal consumption by computing the estimated daily intake, the target hazard quotient (THQ), the total THQ, and the margin of exposure. The mean concentrations of Pb in potato, onion, tomato, lettuce, leek, carrot, wheat, and rice samples were measured as 0.029 ± 0.011, 0.016 ± 0.012, 0.007 ± 0.005, 0.022 ± 0.020, 0.040 ± 0.048, 0.029 ± 0.025, 0.123 ± 0.120, and 0.097 ± 0.059 mg kg−1 wet weight, respectively, and all were below the maximum allowable concentrations set by the European Union. The mean concentrations of Cd in potatoes, onions, tomatoes, lettuce, leeks, carrots, wheat, and rice samples were measured as 0.022 ± 0.013, 0.011 ± 0.009, 0.003 ± 0.003, 0.007 ± 0.005, 0.015 ± 0.024, 0.013 ± 0.011, 0.046 ± 0.043, and 0.049 ± 0.04 mg kg−1 wet weight, respectively, and all were below the permissible levels established by the European Union. The corresponding values for the estimated daily intake of Cd were acceptable and lower than the provisional tolerable daily intake. The THQ and total THQ values of Cd through consumption of all vegetables and cereals were lower than 1. The margin of exposure values for Pb in samples were >1, showing no significant human health risks for both potentially toxic elements. The findings of this study indicated there is no risk associated with exposure to Pb and Cd through the intake of selected vegetables and cereals in western Iran. HIGHLIGHTS
12
CAI, SHIYU, RANDY W. WOROBO, and ABIGAIL B. SNYDER. "Combined Effect of Storage Condition, Surface Integrity, and Length of Shelf Life on the Growth of Listeria monocytogenes and Spoilage Microbiota on Refrigerated Ready-to-Eat Products." Journal of Food Protection 82, no. 8 (July 23, 2019): 1423–32. http://dx.doi.org/10.4315/0362-028x.jfp-18-576.
Full textAbstract:
ABSTRACT Psychrotolerant growth of Listeria monocytogenes in ready-to-eat (RTE) foods increases the risk to food safety, particularly when spoilage does not occur prior to L. monocytogenes growth of >1 log CFU/g. The purpose of this study was to evaluate the relative rates of quality deterioration and L. monocytogenes growth in six product systems (tomatoes, apples, fresh-cut cantaloupe, fresh-cut lettuce, baby spinach, and commercially processed turkey slices) under various conditions of refrigeration temperatures, atmospheres, and quality. Cantaloupe and spinach leaves supported >1 log CFU/g growth of L. monocytogenes before product spoilage at both 4 and 9°C. In some cases, conditions that improved microbial quality by extending shelf life also allowed L. monocytogenes growth of >1 log CFU/g before deterioration due to microbial spoilage. For example, storage with modified atmosphere packaging enhanced L. monocytogenes growth relative to spoilage microbiota in lettuce leaves (1.0-log increase 7 days before spoilage). In contrast, the use of secondary quality produce (i.e., apples, tomatoes, and lettuce with physical damage) reduced shelf life and, consequently, limited the time for L. monocytogenes proliferation. Therefore, spoilage cannot be considered a fail-safe indicator or proxy for limitation of shelf life across refrigerated RTE products.
13
Gyawali, Rabin, Salam A. Ibrahim, Salma H. Abu Hasfa, Shahnaz Q. Smqadri, and Yosef Haik. "Antimicrobial Activity of Copper Alone and in Combination with Lactic Acid againstEscherichia coliO157:H7 in Laboratory Medium and on the Surface of Lettuce and Tomatoes." Journal of Pathogens 2011 (2011): 1–9. http://dx.doi.org/10.4061/2011/650968.
Full textAbstract:
The objective of this study was to evaluate the effect of copper alone and in combination with lactic acid againstE. coliO157:H7 in laboratory medium and on the surface of lettuce and tomatoes. Four strains ofE. coliO157:H7 were individually inoculated into BHI broth containing different concentrations of copper (5, 10, 20, and 40 ppm, w/v), lactic acid (0.1 and 0.2%, v/v), and their combinations. After incubation, aliquots of 1 mL from each sample were withdrawn and plated on BHI agar to determine the bacterial population. Significant growth inhibition (P<0.05) was observed with a combination treatment of copper (40 ppm) and lactic acid (0.2%). The population ofE. coliO157:H7 was reduced by 3.93 and 3.39 log on the surface of lettuce and tomato samples, respectively, when treated with the same combination. This indicates that combination of copper and lactic acid could be used as an effective solution to inhibitE. coliO157:H7 on fresh produce.
14
Sawyer, Leon D. "The Luke et al. Method for Determining Multipesticide Residues in Fruits and Vegetables: Collaborative Study." Journal of AOAC INTERNATIONAL 68, no. 1 (January 1, 1985): 64–71. http://dx.doi.org/10.1093/jaoac/68.1.64.
Full textAbstract:
Abstract Ten laboratories analyzed unfortified and fortified samples of lettuce, tomatoes, and strawberries for organochlorine and organophosphorus pesticides by applicable portions of the comprehensive multipesticide method of Luke et al. The 3 crops were fortified with 6 pesticides, a-BHC, dieldrin, chlorpyrifos, acephate, omethoate, and monocrotophos, each at 3 levels per crop. Included in the 54 fortifications were 16 pairs of blind duplicates: same pesticide, crop, and level. Recoveries were calculated by area comparisons with known reference materials, using the responses obtained from 2 separate element-specific gas chromatographic (GC) systems. The organochlorine pesticides were chromatographed on a methyl silicone column and detected with a Hall 700A electrolytic conductivity detector, and the organophosphorus pesticides were determined with a flame photometric detector after being chromatographed on a specified DEGS column material. Chlorpyrifos was quantitated on both GC systems. Mean recoveries ranged from 82.6% for acephate fortified at 0.5000 ppm in strawberries to 118.1% for 0.0636 ppm fortification of chlorpyrifos in lettuce. Interlaboratory coefficients of variation ranged from 4.0% for 0.6360 ppm fortification of chlorpyrifos in tomatoes to 17.8% for the 0.0636 ppm chlorpyrifos level in lettuce. The procedure features essentially no cleanup before GC and proved comparable to existing multiresidue methods for pesticides of the class types studied, as evidenced by the intra- and interlaboratory measurements of precision and recoveries obtained. The method with the 2 GC systems has been adopted official first action.
15
MOTA, ALAIN, KRISTINA D. MENA, MARCELA SOTO-BELTRAN, PATRICK M. TARWATER, and CRISTÓBAL CHÁIDEZ. "Risk Assessment of Cryptosporidium and Giardia in Water Irrigating Fresh Produce in Mexico." Journal of Food Protection 72, no. 10 (October 1, 2009): 2184–88. http://dx.doi.org/10.4315/0362-028x-72.10.2184.
Full textAbstract:
A rise in foodborne outbreaks in the United States associated with fresh produce has resulted in increased concerns with the importation of fruits and vegetables. Mexico is a major exporter of produce to the United States, particularly tomatoes and bell peppers. A quantitative microbial risk assessment (QMRA) was conducted to evaluate the public health impact of protozoan-laden water irrigating produce in Culiacan, Sinaloa, Mexico. Specifically, a QMRA was conducted to address the human health impact associated with consumption of tomatoes, bell peppers, cucumbers, and lettuce irrigated with water contaminated with Cryptosporidium and Giardia. Yearly infection risks were estimated and assumed a 120-day exposure in a given year. Annual risks range from 9 × 10−6 for Cryptosporidium at the lowest concentration associated with bell peppers to almost 2 × 10−1 for exposure to Giardia on lettuce at the highest detected concentration. With the relatively high number of illnesses resulting from produce-related outbreaks, addressing pre- and postharvest points of contamination for fruits and vegetables consumed raw should be a food industry priority. This research shows how QMRA can be used to interpret microbial contamination data for public health significance and subsequently provide the foundation for guideline development.
16
Frantz, Jonathan M., and Bruce Bugbee. "Acclimation of Plant Populations to Shade: Photosynthesis, Respiration, and Carbon Use Efficiency." Journal of the American Society for Horticultural Science 130, no. 6 (November 2005): 918–27. http://dx.doi.org/10.21273/jashs.130.6.918.
Full textAbstract:
Cloudy days cause an abrupt reduction in daily photosynthetic photon flux (PPF), but we have a poor understanding of how plants acclimate to this change. We used a unique 10-chamber, steady-state, gas-exchange system to continuously measure daily photosynthesis and night respiration of populations of a starch accumulator [tomato (Lycopersicon esculentum Mill. cv. Micro-Tina)] and a sucrose accumulator [lettuce (Lactuca sativa L. cv. Grand Rapids)] over 42 days. All measurements were done at elevated CO2 (1200 μmol·mol-1) to avoid any CO2 limitations and included both shoots and roots. We integrated photosynthesis and respiration measurements separately to determine daily net carbon gain and carbon use efficiency (CUE) as the ratio of daily net C gain to total day-time C fixed over the 42-day period. After 16 to 20 days of growth in constant PPF, plants in some chambers were subjected to an abrupt PPF reduction to simulate shade or a series of cloudy days. The immediate effect and the long term acclimation rate were assessed from canopy quantum yield and carbon use efficiency. The effect of shade on carbon use efficiency and acclimation was much slower than predicted by widely used growth models. It took 12 days for tomato populations to recover their original CUE and lettuce CUE never completely acclimated. Tomatoes, the starch accumulator, acclimated to low light more rapidly than lettuce, the sucrose accumulator. Plant growth models should be modified to include the photosynthesis/respiration imbalance and resulting inefficiency of carbon gain associated with changing PPF conditions on cloudy days.
17
Cranston, Peter S. "A non-biting midge (Diptera: Chironomidae) of horticultural significance." Bulletin of Entomological Research 77, no. 4 (December 1987): 661–67. http://dx.doi.org/10.1017/s0007485300012177.
Full textAbstract:
AbstractSporadic previous reports of chironomid larvae feeding on roots of horticultural plants are reviewed and related to the growing recognition that a particular parthenogenetic species can damage severely indoor horticultural crops, particularly lettuce and young tomatoes. The taxonomy of the pest, Bryophaenocladius furcatus (Kieffer), is assessed, new synonymy proposed and a neotype and lectotype designated. The species is redescribed from the larva, pupa and adult female.
18
BOHAYCHUK, V. M., R. W. BRADBURY, R. DIMOCK, M. FEHR, G. E. GENSLER, R. K. KING, R. RIEVE, and P. ROMERO BARRIOS. "A Microbiological Survey of Selected Alberta-Grown Fresh Produce from Farmers' Markets in Alberta, Canada." Journal of Food Protection 72, no. 2 (February 1, 2009): 415–20. http://dx.doi.org/10.4315/0362-028x-72.2.415.
Full textAbstract:
Previously there was no available information on the levels of indicator bacteria and the prevalence of pathogens in fresh produce grown in Alberta, Canada. Baseline information on the occurrence and levels of Escherichia coli and the prevalence of foodborne pathogens in selected produce items available to consumers from farmers' and public markets in two large urban centers and surrounding areas in Alberta was obtained. A total of 10 large markets with between 1 and 12 produce vendors and 26 small markets with between 1 and 6 produce vendors were sampled from 21 June to 7 October 2007. Lettuce (128 samples), spinach (59 samples), tomatoes (120 samples), carrots (206 samples), green onions (129 samples), and strawberries (31 samples) were analyzed for E. coli, Salmonella, E. coli O157:H7, and Campylobacter spp. Lettuce, spinach, green onion, and strawberry samples were also tested for the presence of Cryptosporidium spp. Information on whether produce was grown using organic or conventional practices was obtained from the produce vendors. E. coli was isolated from 8.2% of the samples that included lettuce, spinach, carrots, and green onions. The bacterial counts ranged from <0.48 to >3.04 Log most probable number per g. E. coli was not isolated from tomatoes or strawberries. The percentage of positive samples ranged from 4.4% for carrots to 27.1% for spinach. Salmonella, E. coli O157:H7, and Campylobacter spp. were not isolated from any of the samples. Cryptosporidium was identified by PCR in one sample of spinach (0.6% of the samples).
19
PANGLOLI, PHILIPUS, YEN-CON HUNG, LARRY R. BEUCHAT, C. HAROLD KING, and ZHI-HUI ZHAO. "Reduction of Escherichia coli O157:H7 on Produce by Use of Electrolyzed Water under Simulated Food Service Operation Conditions." Journal of Food Protection 72, no. 9 (September 1, 2009): 1854–61. http://dx.doi.org/10.4315/0362-028x-72.9.1854.
Full textAbstract:
Treatment of fresh fruits and vegetables with electrolyzed water (EW) has been shown to kill or reduce foodborne pathogens. We evaluated the efficacy of EW in killing Escherichia coli O157:H7 on iceberg lettuce, cabbage, lemons, and tomatoes by using washing and/or chilling treatments simulating those followed in some food service kitchens. Greatest reduction levels on lettuce were achieved by sequentially washing with 14-A (amperage) acidic EW (AcEW) for 15 or 30 s followed by chilling in 16-A AcEW for 15 min. This procedure reduced the pathogen by 2.8 and 3.0 log CFU per leaf, respectively, whereas washing and chilling with tap water reduced the pathogen by 1.9 and 2.4 log CFU per leaf. Washing cabbage leaves for 15 or 30 s with tap water or 14-A AcEW reduced the pathogen by 2.0 and 3.0 log CFU per leaf and 2.5 to 3.0 log CFU per leaf, respectively. The pathogen was reduced by 4.7 log CFU per lemon by washing with 14-A AcEW and 4.1 and 4.5 log CFU per lemon by washing with tap water for 15 or 30 s. A reduction of 5.3 log CFU per lemon was achieved by washing with 14-A alkaline EW for 15 s prior to washing with 14-A AcEW for 15 s. Washing tomatoes with tap water or 14-A AcEW for 15 s reduced the pathogen by 6.4 and 7.9 log CFU per tomato, respectively. Application of AcEW using procedures mimicking food service operations should help minimize cross-contamination and reduce the risk of E. coli O157:H7 being present on produce at the time of consumption.
20
Kouřimská, Lenka, Kristýna Václavíková, Luboš Babička, Martin Koudela, Ludmila Prokůpková, Daniela Miholová, and Dana Kolihová. "The effect of fermented pig slurry fertilization on the quality of vegetables." Acta Universitatis Agriculturae et Silviculturae Mendelianae Brunensis 56, no. 1 (2008): 251–58. http://dx.doi.org/10.11118/actaun200856010251.
Full textAbstract:
Fermented pig slurry as a fermentation residue of biogas plants was used for vegetables fertilization as a replacement of industrial mineral fertilizers. Tomatoes were grown in vessels, celery and spinach in the field, radish and lettuce in the greenhouse. Besides dry matter content determination vegetables were evaluated from the food quality point of view. Is consists of microbiological assessment, nitrates and selected elements (Pb, Cd, As, Zn and Hg) content determination.
21
Lucarini, Massimo, Sabina Lanzi, Laura D’Evoli, Altero Aguzzi, and Ginevra Lombardi-Boccia. "Intake of Vitamin A and Carotenoids from the Italian Population – Results of an Italian Total Diet Study." International Journal for Vitamin and Nutrition Research 76, no. 3 (May 1, 2006): 103–9. http://dx.doi.org/10.1024/0300-9831.76.3.103.
Full textAbstract:
The present study focused on vitamin A and carotenoids (α-and β-carotene, lutein and zeaxanthin, β-cryptoxanthin, lycopene) daily intake from the Italian total diet. The input of some food groups (cereals, vegetables, fruits, milk and dairy, meat and meat products, fish) most responsible for major and minor contributions to the daily intake of these molecules was evaluated. Furthermore the contribution to the dietary intake of β-carotene and lutein of the most consumed vegetables in the market basket of the Italian total diet (beets, brassica vegetables, carrots, chicory, courgette (zucchini), green beans, lettuce, peas, pepper, spinach, tomatoes) was also investigated. Vitamin A daily intake was 855 mg/person/day. The vegetables food group made the greatest contribution (37%), followed by the meat and meat products food group (23%). The Italian total diet provided 14.3 mg/person/day of carotenoids; lycopene was the highest (7.4 mg/day), followed by lutein + zeaxanthin (4 mg/day), β-carotene (2.6 mg/day), α-carotene (0.15 mg/day), and β-cryptoxanthin (0.17 mg/day). Carrots and tomatoes were the main sources of β-carotene in the diet, otherwise the daily consumption of leafy vegetables (spinach, beets, lettuce) made the main contribution to lutein + zeaxanthin daily intake.
22
RAIDEN, RENEE M., SUSAN S. SUMNER, JOSEPH D. EIFERT, and MERLE D. PIERSON. "Efficacy of Detergents in Removing Salmonella and Shigella spp. from the Surface of Fresh Produce." Journal of Food Protection 66, no. 12 (December 1, 2003): 2210–15. http://dx.doi.org/10.4315/0362-028x-66.12.2210.
Full textAbstract:
Fresh produce has been implicated in several foodborne disease outbreaks. Produce surfaces can be primary sites of contamination during production and handling. One approach to reduce contamination is to treat fresh produce with rinsing agents. In this study, different detergent agents were used at 22 and 40°C to determine their efficacy in removing Salmonella and Shigella spp. from the surfaces of strawberries, tomatoes, and green-leaf lettuce. Produce was inoculated at 22°C with a cocktail of nalidixic acid–resistant organisms (6 to 6.5 log CFU/ml). After air drying for 1 h, samples were rinsed with either 0.1% Tween 80, 0.1% sodium lauryl sulfate (SLS), or water (control) at 22 or 40°C. Rinse solutions were spiral plated onto tryptic soy agar supplemented with 50 mg of nalidixic acid per liter. In trials involving strawberries and lettuce, Salmonella and Shigella were removed at levels of 4 and 3 log CFU/ml, respectively, except from Salmonella-inoculated strawberries rinsed with SLS, for which minimal removal rates were 1.5 log CFU/ml at 22°C and <1 log CFU/ml at 40°C. When whole strawberries were analyzed after rinsing with SLS, few organisms were recovered. This result suggests that SLS may have a lethal or sublethal effect on Salmonella, especially when a 40°C solution is used. Salmonella and Shigella removal rates for tomatoes were 1 and 1.5 log CFU/ml lower, respectively, than those for strawberries or lettuce. Overall, detergents were no more effective in removing organisms from produce than water was. The detergents examined would not constitute effective overall produce rinse treatments.
23
PARTYKA, MELISSA L., RONALD F. BOND, JEFF FARRAR, ANDY FALCO, BARBARA CASSENS, ALONZA CRUSE, and EDWARD R. ATWILL. "Quantifying the Sensitivity of Scent Detection Dogs To Identify Fecal Contamination on Raw Produce." Journal of Food Protection 77, no. 1 (January 1, 2014): 6–14. http://dx.doi.org/10.4315/0362-028x.jfp-13-249.
Full textAbstract:
Consumption of raw produce commodities has been associated with foodborne outbreaks in the United States. In a recent Centers for Disease Control and Prevention report outlining the incidence of food-related outbreaks from 1998 to 2008, produce of all kinds were implicated in 46% of illnesses and 23% of deaths. Methods that quickly identify fecal contamination of foods, including produce, will allow prioritization of samples for testing during investigations and perhaps decrease the time required to identify specific brands or lots. We conducted a series of trials to characterize the sensitivity and specificity of scent detection dogs to accurately identify fecal contamination on raw agricultural commodities (romaine lettuce, spinach, cilantro, and roma tomatoes). Both indirect and direct methods of detection were evaluated. For the indirect detection method, two dogs were trained to detect contamination on gauze pads previously exposed to produce contaminated with feces. For the direct detection method, two dogs were trained to identify fecal contamination on fresh produce. The indirect method did not result in acceptable levels of sensitivity except for the highest levels of fecal contamination (25 g of feces). Each dog had more difficulty detecting fecal contamination on cilantro and spinach than on roma tomatoes. For the direct detection method, the dogs exhibited >75% sensitivity for detecting ≥0.25 g of feces on leafy greens (cilantro, romaine lettuce, and spinach) and roma tomatoes, with sensitivity declining as the amount of feces dropped below 0.025 g. We determined that use of a scent detection dog to screen samples for testing can increase the probability of detecting ≥0.025 g of fecal contamination by 500 to 3,000% when samples with fecal contamination are rare (≤1%).
24
Pajovic, I., S. Širca, B. Geric Stare, and G. Urek. "The Incidence of Root-Knot Nematodes Meloidogyne arenaria, M. incognita, and M. javanica on Vegetables and Weeds in Montenegro." Plant Disease 91, no. 11 (November 2007): 1514. http://dx.doi.org/10.1094/pdis-91-11-1514b.
Full textAbstract:
Root-knot nematodes (Meloidogyne spp.) are common pathogens that parasitize vegetables and other crops and cause significant yield reductions worldwide. In the early spring of 2006, severe plant stunting, chlorosis, and extensive root galling were observed on cucumber plants grown in a greenhouse on Zeta plain, Zetska ravnica, Montenegro. In the summer and autumn of 2006, infected roots of different crops were collected from greenhouses and vegetable production fields of Zeta plain, which represents the largest area of Montenegro's vegetable production. Several vegetable crops were found to be infected with root-knot nematodes, including tomato (Lycopersicon esculentum Mill.), squash (Cucurbita pepo L.), cucumber (Cucumis sativus L.), pepper (Capsicum annuum L.), and lettuce (Lactuca sativa L.). Symptoms on these crops included root-galling, leaf chlorosis, and stunting. Heavily infected tomato plants growing in two greenhouses also displayed early flower and fruit drop. Nematode species were determined based on characterization of (i) female perineal patterns, (ii) male and second-stage juvenile morphology (2,3), and (iii) esterase and malate dehydrogenase phenotypes (PhastSystem; Amersham Biosciences, Piscataway, NJ) from young egg-laying females (1). The most prevalent species was M. incognita, which was isolated from the roots of tomatoes, peppers, cucumbers, and lettuce from nine locations. Meloidogyne arenaria was detected at three locations from the roots of tomatoes grown in a greenhouse and the weeds Convolvulus arvensis L. and Solanum nigrum L., which were growing in open fields in separate locations. M. javanica was found on tomato and squash in the same field where M. arenaria was also found on S. nigrum. M. javanica was isolated from tomato and squash. In this study, we found high incidence of Meloidogyne spp. in intensive vegetable production areas of Montenegro. The implementation of an effective integrated pest management program is essential for future use of infested areas. To our knowledge, this is the first report of M. arenaria, M. incognita, and M. javanica from Montenegro. References: (1) P. R. Esbenshade and A. C. Triantaphyllou. J. Nematol. 17:6, 1985. (2) S. B. Jepson. Identification of Root-Knot Nematodes. CAB International, Wallingford, UK, 1987. (3) G. Karssen. The Plant-Parasitic Nematode Genus Meloidogyne Göldi, 1892 (Tylenchida) in Europe. Koninklijke Brill NV, Leiden, the Netherlands, 2002.
25
SONG, YUANYUAN, and XUETONG FAN. "Hydrogen Peroxide Residue on Tomato, Apple, Cantaloupe, and Romaine Lettuce after Treatments with Cold Plasma–Activated Hydrogen Peroxide Aerosols." Journal of Food Protection 84, no. 8 (April 1, 2021): 1304–8. http://dx.doi.org/10.4315/jfp-21-051.
Full textAbstract:
ABSTRACT Hydrogen peroxide (H2O2) has long been studied as an aqueous sanitizer to enhance microbial safety of fresh produce. Recently, we demonstrated that cold plasma–activated H2O2 aerosols, hereafter called ionized hydrogen peroxide (iHP), reduced populations of Salmonella, Listeria, and Escherichia coli by up to 5.5 log on surfaces of various produce items. However, the amount and fate of H2O2 residue left on fresh produce after treatments have not been evaluated. In the present study, H2O2 residue levels on apples, tomatoes, cantaloupe, and romaine lettuce were analyzed after treatments with 7.8% iHP at conditions that had been optimized and tailored for Salmonella reductions and each produce item. Results showed that higher residue levels were found on lettuce than on cantaloupe, tomatoes, and apples immediately after treatments. During storage at 10 and 22°C, H2O2 levels decreased rapidly and fell below 1 mg/kg within 1 day after treatments for all fresh produce items. Furthermore, the decrease was faster at 22°C than at 10°C. Most importantly, the levels of H2O2 residue on the fresh produce items were lower than those after wash with 1% H2O2 for 1 min. Overall, our results demonstrated that levels of H2O2 residue on fresh produce surfaces decomposed rapidly after treatment with iHP and did not appear to pose a safety concern after 1 day of storage. HIGHLIGHTS
26
GORSKI, LISA, and ANITA S. LIANG. "Effect of Enrichment Medium on Real-Time Detection of Salmonella enterica from Lettuce and Tomato Enrichment Cultures." Journal of Food Protection 73, no. 6 (June 1, 2010): 1047–56. http://dx.doi.org/10.4315/0362-028x-73.6.1047.
Full textAbstract:
Three enrichment broths commonly used for detection of Salmonella (buffered peptone water [BPW], tryptic soy broth [TSB], and universal preenrichment broth [UPB]) were compared for use in real-time SYBR Green PCR detection of Salmonella introduced into enrichment cultures made from store-bought lettuce and tomatoes. The produce served as a source of normal plant microbiota to measure how well DNA-based detection methods for Salmonella work in a suspension of plant-associated bacteria that may be closely related to Salmonella. A qualitative assessment of the background microbiota that grew in the three enrichment broths cultures from tomato and lettuce samples revealed that different bacteria predominated in the different broths. Results obtained with five produce-related outbreak Salmonella strains and PCR primers directed toward three different Salmonella genes suggest that the ability to detect Salmonella from these enrichment cultures by real-time PCR was 10 to 1,000 times better with TSB enrichment cultures. Detection levels were similar between the different enrichment media when an immunomagnetic separation method was used; however, the immunological technique did not enhance detection from TSB enrichment cultures. Detection could be affected by the medium and by the background microbiota. An immunomagnetic separation method may be useful in BPW and UPB enrichment cultures but not in TSB enrichment cultures.
27
Miller, Nathan D., P. M. Davidson, and Doris H. D’Souza. "Real-time reverse-transcriptase PCR for Salmonella Typhimurium detection from lettuce and tomatoes." LWT - Food Science and Technology 44, no. 4 (May 2011): 1088–97. http://dx.doi.org/10.1016/j.lwt.2010.08.003.
Full text
28
Crozier, Alan, Michael E. J. Lean, Morag S. McDonald, and Christine Black. "Quantitative Analysis of the Flavonoid Content of Commercial Tomatoes, Onions, Lettuce, and Celery." Journal of Agricultural and Food Chemistry 45, no. 3 (March 1997): 590–95. http://dx.doi.org/10.1021/jf960339y.
Full text
29
FARBER, J. M., G. W. SANDERS, and M. A. JOHNSTON. "A Survey of Various Foods for the Presence of Listeria Species." Journal of Food Protection 52, no. 7 (July 1, 1989): 456–58. http://dx.doi.org/10.4315/0362-028x-52.7.456.
Full textAbstract:
Various retail foods were analyzed for the presence of Listeria spp. One hundred ten samples of vegetables including lettuce, celery, tomatoes, and radishes, and 14 samples of pasteurized milk, were found to be free of L. monocytogenes. In contrast 9 of 16 (56.3%) chicken legs, 38 of 44 (86.4%) ground meats, and 6 of 30 (20%) fermented sausages contained the organism. Of 530 samples of ice cream products obtained at the manufacturing level, only 2 were positive for L. monocytogenes.
30
LIN, CHIA-MIN, JEONGMOK KIM, WEN-XIAN DU, and CHENG-I. WEI. "Bactericidal Activity of Isothiocyanate against Pathogens on Fresh Produce†." Journal of Food Protection 63, no. 1 (January 1, 2000): 25–30. http://dx.doi.org/10.4315/0362-028x-63.1.25.
Full textAbstract:
The bactericidal activity of allyl and methyl isothiocyanate (AITC and MITC) was tested with a rifampicin-resistant strain of Salmonella Montevideo and streptomycin-resistant strains of Escherichia coli O157:H7 and Listeria monocytogenes Scott A. Iceberg lettuce inoculated with high (107 to 108 CFU/g) and low (103 to 104 CFU/g) concentrations of bacterial pathogens was treated with AITC and MITC in sealed containers at 4°C for 4 days. AITC showed stronger bactericidal activity than MITC against E. coli O157:H7 and Salmonella Montevideo, whereas MITC showed stronger activity against L. monocytogenes than E. coli O157:H7 and Salmonella Montevideo. Up to 8-log reduction occurred with E. coli O157:H7 and Salmonella Montevideo on lettuce following treatment with vapor generated from 400 μl of AITC for 2 and 4 days, respectively. AITC was used to treat tomatoes inoculated with Salmonella Montevideo on stem scars and skin and apples inoculated with E. coli O157:H7 on stem scars. The bactericidal effect of AITC varied with bacteria species and exposure time. Salmonella Montevideo inoculated on tomato skin was more sensitive to AITC than that on stem scars. Treatment with vapor generated from 500 μl of AITC caused an 8-log reduction in bacteria on tomato skin but only a 5-log reduction on tomato stem scars. The bactericidal activity of AITC was weaker for E. coli O157:H7 on apple stem scars; only a 3-log reduction in bacteria occurred when 600 μl of AITC was used.
31
Dari, Linda, Ahmad ADDO, and Komla Agbeko DZISI. "Determination of Pesticide Residuals in Soil and Tomato Fruits from Two Tomato Production Areas in northern Ghana." Ghana Journal of Science, Technology and Development 6, no. 2 (March 1, 2020): 37–44. http://dx.doi.org/10.47881/167.967x.
Full textAbstract:
Tomato fruit (Lycopersicon esculentum Mill) is an important vegetable commodity in Ghana, as it is consumed daily in many households either heat-treated or without any form of heat treatments. Tomato production is a major source of income for many smallholder producers in Northern Ghana especially through dry season farming when the major supply of tomatoes from Southern Ghana is exhausted. Research conducted for the past decade confirmed the presence of pesticide residues in fruits and vegetables such as cabbage, onion, cucumber, lettuce, tomatoes, okra and pepper. The objective of this study was to identify and estimate pesticide residual levels in the soil and tomato fruits in comparison with the maximum allowable residual limits. The research was carried out in two production communities namely Doba where the “Burkina” variety is mostly grown in the Kassena Nankana East District of the Upper East Region and Bunglung where the “Wosowoso” variety is cultivated in the Savelugu/Nanton Municipality of Northern Region. Soil samples were collected for residue determination before transplanting of tomato seedlings. Matured and ripe tomato fruits were also collected for the determination of the presence and amount of pesticide residues. All soil and plant samples were analysed using high performance liquid chromatography to determine the presence of twenty-four organochlorines and thirteen organophosphate pesticide residues. From the analysis, pesticide residues were present in different variations which ranged from 0.002 – 0.033 and 0.003 – 0.022 (soils) and 0.330 – 1.187 and 0.002 – 0.088 (fruits) for organochlorines and organophosphates respectively for both communities. Levels of pesticide residues were generally above the acceptable maximum residue limits as farmer practices produced fruits with more pesticide residues since the land areas could have been predisposed with residues from previous seasons for other food crops, which could be translocated into the tomato plant and through into the fruits. The presence of pesticide residues could also be attributed to the influence of run-off and drift from other cultivated lands. For effective determination of pesticides residues in the tomato plants, it is essential to use uncontaminated soil and water to facilitate the efficient estimation of pesticide residues in tomatoes and plants in general.
32
Suleiman, F., A. A. Nuhu, K. I. Omoniyi, and Z. I. Yashim. "DETERMINATION OF ORGANOCHLORINE PESTICIDE RESIDUES IN SOME VEGETABLES AND FRUIT BY QuEChERS TECHNIQUES AND GAS CHROMATOGRAPHY /MASS SPECTROMETRY." FUDMA JOURNAL OF SCIENCES 4, no. 2 (July 3, 2020): 365–70. http://dx.doi.org/10.33003/fjs-2020-0402-223.
Full textAbstract:
The concentrations of organochlorine pesticide residues were analysed in some vegetables and fruit (spinach, lettuce, cabbage, tomatoes, carrots and onions) grown at Dagachi farming areas along River Galma of Zaria in Kaduna State, Nigeria. Sample collection and preparation were carried out using standard procedures. The concentrations of all the pesticides in the fruits and vegetables samples were analysed using quick easy cheap effective rugged and safe (QuEChERS) multi- residue extraction and clean up techniques, followed by gas chromatography – mass spectrometry (GC – MS). The most commonly detected organochlorine pesticide residues in the entire samples analysed are lindane, delta – BHC, heptachlor epoxide (B), endosulfan I, dieldrin, and endosulfan II. Furthermore, the results of the study shows that the mean concentration of these organochlorines pesticide detected were higher in onion and spinach with heptachlor epoxide (B) having concentrations 2.303 mg/kg and 2.011 mg/kg respectively. Likewise, endosulfan II (1.433 mg/kg) in lettuce was observed. Heptachlor epoxide (B) detected were also very high in other samples such as carrot, cabbage, and tomatoes and with values 0.600 mg/kg, 0.716 mg/kg, and 0.524 mg/kg respectively. Indeed, these concentrations of all the organochlorine pesticides detected in the fruit and vegetables samples analysed were observed to be at alarming levels, much higher than the maximum residue limits (MRLs) by the Codex 2009 (WHO and FAO) except for lindane with values 0.007 mg/kg and 0.01 mg/kg in carrot and onions respectively
33
MUKHERJEE, AVIK, DORINDA SPEH, ELIZABETH DYCK, and FRANCISCO DIEZ-GONZALEZ. "Preharvest Evaluation of Coliforms, Escherichia coli, Salmonella, and Escherichia coli O157:H7 in Organic and Conventional Produce Grown by Minnesota Farmers." Journal of Food Protection 67, no. 5 (May 1, 2004): 894–900. http://dx.doi.org/10.4315/0362-028x-67.5.894.
Full textAbstract:
Microbiological analyses of fresh fruits and vegetables produced by organic and conventional farmers in Minnesota were conducted to determine the coliform count and the prevalence of Escherichia coli, Salmonella, and E. coli O157:H7. A total of 476 and 129 produce samples were collected from 32 organic and 8 conventional farms, respectively. The samples included tomatoes, leafy greens, lettuce, green peppers, cabbage, cucumbers, broccoli, strawberries, apples, and seven other types of produce. The numbers of fruits and vegetables was influenced by their availability at participating farms and varied from 11 strawberry samples to 108 tomato samples. Among the organic farms, eight were certified by accredited agencies and the rest reported the use of organic practices. All organic farms used aged or composted animal manure as fertilizer. The average coliform counts in both organic and conventional produce were 2.9 log most probable number per g. The percentages of E. coli–positive samples in conventional and organic produce were 1.6 and 9.7%, respectively. However, the E. coli prevalence in certified organic produce was 4.3%, a level not statistically different from that in conventional samples. Organic lettuce had the largest prevalence of E. coli (22.4%) compared with other produce types. Organic samples from farms that used manure or compost aged less than 12 months had a prevalence of E. coli 19 times greater than that of farms that used older materials. Serotype O157:H7 was not detected in any produce samples, but Salmonella was isolated from one organic lettuce and one organic green pepper. These results provide the first microbiological assessment of organic fruits and vegetables at the farm level.
34
Stegarus, Diana Ionela, Roxana Elena Ionete, Ecaterina Lengyel, and Marius Gheorghe Miricioi. "Advanced Identification and Quantification of Pesticide Residues in Vegetables by GC-ToFMS Technique." Revista de Chimie 71, no. 4 (May 5, 2020): 220–29. http://dx.doi.org/10.37358/rc.20.4.8060.
Full textAbstract:
The identification and quantification of a large range of pesticide residues (e.g. fungicides, insecticides, acaricides) in vegetables from Romania markets, in Maramures, Alba Iulia and Botosani region, was performed by gas-chromatography coupled with time-of-flight mass spectrometry (GC-ToFMS) to better assess the impact of agricultural practices that may result from `accidental` application of higher doses of treatment solutions. The ion chromatograms obtained by GC-ToFMS enabled us to easily quantify at ppb level and to record the entire spectrum at high speeds (up to 500 spectra/second) without losing of the data quality. Although, most of the pesticide residues detected were below the limits set by the law, the results highlighted concentrations that exceeded the maximum allowed for toclofos-methyl and malathion from recent treatments and still high levels of alpha- and beta-hexachlorocyclohexane (mostly in green lettuce) from the historical treatments. It was also evidenced that green lettuce accumulated more than 77% higher amount of pesticides than cucumber, green beans and tomatoes.
35
GUO, SHUANGHUAN, RUNZE HUANG, and HAIQIANG CHEN. "Evaluating a Combined Method of UV and Washing for Sanitizing Blueberries, Tomatoes, Strawberries, Baby Spinach, and Lettuce." Journal of Food Protection 82, no. 11 (October 17, 2019): 1879–89. http://dx.doi.org/10.4315/0362-028x.jfp-18-524.
Full textAbstract:
ABSTRACT We assessed a fresh produce decontamination system using a combined method of UV and washing (water-assisted UV [WUV]) in different scales. The system used tap water to wash fresh produce while exposing it to UV light. First, the reduction of Salmonella in tap water under UV treatment (1 to 1,740 mJ/cm2) was determined. Increasing the UV dose significantly (P < 0.05) increased the Salmonella reduction in wash water, and UV intensity of more than 2 mW/cm2 could reduce Salmonella in tap water to below 1 CFU/mL given enough processing time (more than 1 min; UV dose of 120 mJ/cm2). Then, the decontamination effectiveness of a small WUV system was tested on blueberries (50 g). Blueberries were spot or dip inoculated with a Salmonella cocktail and treated by the small WUV system (200 mL of water). In general, WUV treatments achieved significantly better Salmonella inactivation than tap water wash; tap water wash (10 min) and 2 mW/cm2 WUV treatment (with a UV dose of 1,200 mJ/cm2) reduced populations of spot-inoculated Salmonella on blueberries by 2.44 and 5.45 log, respectively. Compared with spot-inoculated Salmonella on blueberries, dip-inoculated Salmonella was more difficult to be inactivated by WUV treatments. Then, the decontamination effectiveness of WUV treatments was tested on blueberries (170 g), tomatoes (290 g), strawberries (170 g), baby spinach (60 g), and lettuce (60 g) using a larger WUV system. In general, 10 min of 29 mW/cm2 WUV treatment (a high UV dose of 17,400 mJ/cm2) resulted in significantly better Salmonella inactivation than tap water wash (for 10 min) regardless the inoculation method, agreeing with the results of the small-scale study. For both spot- and dip-inoculated lettuce, no significant difference (P > 0.05) in Salmonella inactivation by WUV treatments was observed when the quantity of lettuce increased from 50 to 100 g.
36
KIM, SE-RI, YOHAN YOON, WON-IL KIM, KYEONG-HUN PARK, HYE-JEONG YUN, DUCK HWA CHUNG, JONG CHUL YUN, and KYOUNG YUL RYU. "Comparison of Sample Preparation Methods for the Recovery of Foodborne Pathogens from Fresh Produce." Journal of Food Protection 75, no. 7 (July 1, 2012): 1213–18. http://dx.doi.org/10.4315/0362-028x.jfp-11-420.
Full textAbstract:
Sample preparation methods (pummeling, pulsifying, sonication, and shaking by hand) were compared for achieving maximum recovery of foodborne pathogens from iceberg lettuce, perilla leaves, cucumber, green pepper, and cherry tomato. Antimicrobial and dehydration effects also were examined to investigate causes of poor recovery of pathogens. Each produce type was inoculated with Escherichia coli O157:H7, Salmonella Typhimurium, Listeria monocytogenes, Staphylococcus aureus, and Bacillus cereus at 6.0 log CFU/cm2, and samples were prepared using the four methods. Bacterial populations recovered from the five types of produce were significantly different (P < 0.05) according to sample preparation methods and produce type. The bacterial populations recovered from pummeled and pulsified samples were higher (P < 0.05) than those recovered from sonicated and hand-shaken samples, except for cherry tomato. The number of bacteria recovered from produce was reduced (P < 0.05) from that of the inoculum by 0.16 to 2.69 log CFU/cm2. Although extracts of iceberg lettuce, perilla leaves, cucumber, and green pepper had no antimicrobial activity, the populations of E. coli O157:H7, Salmonella Typhimurium, B. cereus, and L. monocytogenes in cherry tomato extract were slightly reduced after these treatments (P < 0.05). The pathogen populations on perilla leaves and cherry tomatoes decreased by >2 log CFU/cm2 after exposure to 40% relative humidity for 1 h. No reduction was observed when the five pathogens were exposed to 90% relative humidity. These data suggest that pummeling and pulsifying are optimal sample preparation methods for detection of microorganisms. Acidic produce such as cherry tomato should be treated with a method that does not cause sample breakdown so that acid stress on the bacteria can be minimized. Dehydration stress also affects recovery of pathogens from produce.
37
Stirzaker, RJ, BG Sutton, and N. Collis-George. "Soil management for irrigated vegetable production. I. The growth of processing tomatoes following soil preparation by cultivation, zero-tillage and an in situ-grown mulch." Australian Journal of Agricultural Research 44, no. 4 (1993): 817. http://dx.doi.org/10.1071/ar9930817.
Full textAbstract:
A sequence of lettuce and tomato crops was grown in a field experiment on a sandy loam soil in order to study the relationship between soil tillage and plant growth under the near optimal water and nutrient conditions which are characteristic of vegetable production. This paper describes the performance of processing tomato crops, grown over two seasons under a range of soil management systems. The soil management systems included a cultivated and a zero-tillage treatment, as well as a zero-tillage treatment which followed a crop of subterranean clover (Trifoliurn subterraneum L.). The subterranean clover was sown in autumn and senesced in early summer to form an in-situ mulch. The bulk density of the soil in the zero-tillage treatment was high, and this was associated with a large reduction in vegetative growth, compared with the cultivated treatment. The bulk density of the soil was also high in the treatment where the subterranean clover was grown, but the vegetative growth of tomatoes was equal to that in the cultivated treatment. Despite the large differences in vegetative growth among treatments, there was no significant difference in the fruit yield. These results show that processing tomatoes can be successfully grown under zero-tillage when irrigation and fertilizer are well managed, and that vegetative growth and fruit yield are poorly correlated. The in-situ mulch of subterranean clover improved the physical conditions of the soil compared to the zero-tillage treatment, successfully controlled weeds and reduced soil erosion, but at the cost of having land out of production during the winter.
38
Kukhtyn, Mykola, Yulia Horiuk, Tetiana Yaroshenko, Svitlana Laiter-Moskaliuk, Viktoria Levytska, and Antonina Reshetnyk. "MONITORING THE CONTENT OF NITRATES IN VEGETABLES AND THE INFLUENCE OF THE PICKLING TECHNOLOGY ON THE DENITRIFICATION PROCESS." EUREKA: Life Sciences 1 (January 30, 2018): 3–10. http://dx.doi.org/10.21303/2504-5695.2018.00528.
Full textAbstract:
The aim of the work was to determine the concentration of nitrites in vegetable products (tomatoes, cucumbers, white cabbage, table beet, carrot, potatoes, onion and green onion, lettuce, spinach and parsley), realized at markets of the cities Ternopil, Kamianets-Podilskyi and Chernivtsi (Ukraine), to separate the distribution of nitrates in vegetables and also to study the influence of lactic microflora on the nitrate content at pickling tomatoes. It was established, that vegetables with the maximum exceed of maximum permissible concentration (MPC) by the nitrate content up to 1,6 times for products of closed soil are realized at markets. For open soil MPC exceed was in average 2,1 times. It was revealed, that most realized samples of tomatoes and leaf salad vegetables have the over-normative exceed of nitrates up to 35 %, and onion – the least one – 20 %. It was established, that nitrates accumulate in different parts of a fruit. In cucumbers, carrot, potato and table beet, the least quantity of nitrates accumulate in the external part of vegetables (near the surface), and the most one – in the central part. At the same time in cabbage and tomatoes, on the contrary, the least quantity – in the central part, the most one – in the area near the base of vegetables (stump). It was established, that at pickling tomatoes with the nitrate content within MPC lactic fermentation takes place with the intensive growth of titrated acidity, the decrease of the nitrate content takes place at this process. Under conditions of pickling tomatoes with the nitrate content two times more than MPC, the pickling process is a bit decelerated, but the nitrate content decreases to the safe level in a finished product. It was established, that vegetables with the nitrates quantity within 1500 mg/kg and more cannot be used in the pickling technology because of the bacteriological influence of nitrates on lactic microflora. Vegetables with such nitrate content must be obligatory condemned.
39
Yang, Teng, and Hye-Ji Kim. "Characterizing Nutrient Composition and Concentration in Tomato-, Basil-, and Lettuce-Based Aquaponic and Hydroponic Systems." Water 12, no. 5 (April 29, 2020): 1259. http://dx.doi.org/10.3390/w12051259.
Full textAbstract:
Aquaponic nutrient studies often use various types of water containing high levels of mineral nutrients for water supply, making it difficult to accurately determine deficient nutrients limiting crop yield and quality across the systems. To avoid interference with background nutrients, we used reverse osmosis water in this study. The objectives were to identify critical nutrients that affect the yield and quality of cherry tomato-, basil-, and lettuce by characterizing nutrient composition and concentration in aquaponic systems in comparison to hydroponic systems. Daily release rate (mg L−1) of macronutrients derived from fish feed (41% protein, 1.1% phosphorus, 1% fish weight) was in decreasing order of SO4–S (16) > PO4–P (2.4) > NO3–N (1.0) > K (0.8) > Cl (0.5) > NH4–N (0.4) > Ca (0.2) > NO2–N (0.13) > Na (0.11) > Mg (0.02), in which daily inputs of Mg and Ca in aquaponics were found to be only 1–2% and 4–6%, respectively, of those in hydroponics. Subsequently, the average concentrations of all nutrients were significantly lower in aquaponics than in hydroponics during a 3-month production except for Cl, NH4–N, NO2–N, and Na. The concentration of Mg remained below 5 mg L−1 in all aquaponic systems, while the concentration of Ca rapidly decreased in tomato-based aquaponics, especially during fruiting. SPAD value (chlorophyll content) was associated with concentrations of leaf N, Mg, and/or Ca. Specifically, lower SPAD value was correlated with lower leaf Mg and Ca for tomato and lower leaf Mg for basil but neither Mg nor Ca for lettuce. The aquaponic solution contained nearly six-times higher Na than the hydroponic solution, resulting in three-times higher Na concentration in the edible portion of the crops. Compared to a lettuce-based aquaponic system, tomato- and basil-based systems retained more desirable water quality parameters (i.e., stable pH, lower temperature), had lower electrical conductivity (EC) via greater biomass production and, therefore, more efficient nutrient removal, and had lower feed conversion rate and higher fish biomass increment. Regardless of crop species, vegetative shoot biomass was significantly reduced in aquaponics than in hydroponics. However, the marketable yield of tomatoes was similar between aquaponics and hydroponics, while those of basil and lettuce were reduced in aquaponics by 56% and 67%, respectively, in comparison to hydroponics. Our results highlighted potential solutions to design proper nutrient management practices essential for the development of successful aquaponic production systems. Considering that ingested fish feed does not provide sufficient levels of Mg and/or Ca for crop production, it is suggested to supplement Mg before crop transplanting and Ca before fruiting of fruity crops to improve crop growth and quality in aquaponic systems, especially when high-quality water is used for water supply.
40
BARDELL, D. "Survival of Herpes Simplex Virus Type 1 on Some Common Foods Routinely Touched before Consumption." Journal of Food Protection 60, no. 10 (October 1, 1997): 1259–61. http://dx.doi.org/10.4315/0362-028x-60.10.1259.
Full textAbstract:
Droplets of saliva containing herpes simplex virus type 1 were placed on the skin of tomatoes and the upper surface of lettuce leaves. There was no loss of virus infectivity titer at refrigerator temperature (2°C) at any time examined up to 1 h, the longest period tested. At room temperature (22 to 24°C) there was a 2-log drop in titer between 30 and 60 min, but some infectious virus was still present at 1 h. The virus-containing saliva remained in a liquid state at 2°C. At 22 to 24°C the droplets became dry at approximately 50 min. Implications of the findings are discussed.
41
Barak, Jeri D., Lara C. Kramer, and Ling-yun Hao. "Colonization of Tomato Plants bySalmonella entericaIs Cultivar Dependent, and Type 1 Trichomes Are Preferred Colonization Sites." Applied and Environmental Microbiology 77, no. 2 (November 12, 2010): 498–504. http://dx.doi.org/10.1128/aem.01661-10.
Full textAbstract:
ABSTRACTNontyphoid salmonellosis caused bySalmonella entericais the most common bacterial food-borne illness in humans, and fresh produce, including tomatoes, is a common vehicle. Accumulating data indicate that human enteric pathogenic bacteria, includingS. enterica, interact actively with plants. Tomato plants were inoculated withS. entericato evaluate plausible contamination routes and to determine if the tomato cultivar affectsS. entericacolonization.S. entericapopulation levels on tomato leaves were cultivar dependent.S. entericalevels onSolanum pimpinellifolium(West Virginia 700 [WVa700]) were lower than onS. lycopersicumcultivars.S. entericapreferentially colonized type 1 trichomes and rarely interacted with stomata, unlike what has been reported for cut lettuce leaves. EarlyS. entericaleaf colonization led to contamination of all fruit, with levels as high as 105CFU per fruit. Reduced bacterial speck lesion formation correlated with reducedS. entericapopulations in the phyllosphere. Tomato pedicels and calyxes also harbored largeS. entericapopulations following inoculation via contaminated water postharvest. WVa700 green fruit harbored significantly smallerS. entericapopulations than did red fruit orS. lycopersicumfruit. We found that plants irrigated with contaminated water had largerS. entericapopulations than plants grown from seeds planted in infested soil. However, both routes of contamination resulted in detectableS. entericapopulations in the phyllosphere. PhyllosphereS. entericapopulations pose a risk of fruit contamination and subsequent human disease. RestrictingS. entericaphyllosphere populations may result in reduced fruit contamination. We have identified WVa700 as a tomato cultivar that can restrictS. entericasurvival in the phyllosphere.
42
Camargo Filho, Waldemar P., and Felipe P. Camargo. "A quick review of the production and commercialization of the main vegetables in Brazil and the world from 1970 to 2015." Horticultura Brasileira 35, no. 2 (April 2017): 160–66. http://dx.doi.org/10.1590/s0102-053620170202.
Full textAbstract:
ABSTRACT In the biennium 2013-14, the world produced 1,134.27 million tons of vegetables annually. The production of garlic, onion, potato, tomato and watermelon accounted for 66.5% of the total. Brazil, in 2012, considering 40 vegetables, produced around 23 million tons, in 900.0 thousand hectares. Potatoes, tomatoes (table and processing), onions, watermelons, carrots, sweet potatoes, lettuce and cabbage, the main vegetables in Brazil, accounted for 64.0% of the total. This work presents the evolution of production, commercialization, and availability of garlic, onions, potatoes, tomatoes and watermelons in Brazil and in the world. In Brazil, the work focused on two distinct periods: 1970-1990 {when the Support Program for Production and Commercialization of Horticultural Products (PROHORT) was implemented} and 1990-2012 (the globalization period). In 13 years (1977-1990), PROHORT succeeded in inducing the modernization of production of fruits, vegetables, and poultry products, enabling the sector to compete in the world market, especially after 1990, with the market opening and the establishment of MERCOSUR. In the 22-year period from 1990-2012, despite the initial difculties with the commercial opening and internal economic instabilities, production and availability of garlic, onion, potato, tomato and watermelon continued to evolve in Brazil. The horticultural sector advanced in incorporating technologies and in modernizing, stimulated by the market expansion due to both the population growth (33%) observed in Brazil in this period and real gains in Brazilians’ income owed to inflation control. In the world scenario, the work discusses the same aspects for these fve vegetables in the period 2001-2013. The analysis of the initial and fnal triennia of this period showed vegetable production increasing 30.3% in the world and 24.4% in Brazil. In both contexts, gains in yield were the main driver of expansion of production, and yield increase came mainly from the use of improved cultivars, especially hybrids.
43
Susan, A. I., E. Sasmita, E. Yulianto, F. Arianto, M. Restiwijaya, A. W. Kinandana, and M. Nur. "Ozone application to extend shelf life of vegetables by microbial growth inhibition." MATEC Web of Conferences 197 (2018): 02004. http://dx.doi.org/10.1051/matecconf/201819702004.
Full textAbstract:
Ozone has been used to extend the shelf life of vegetables by inhibiting the decomposing microbial growth. The study was conducted using six types of vegetables; i.e. broccoli, tomato, mustard, celery, leek, and lettuce; treated and stored using ozonation techniques. The six types of vegetables were divided into two treatment groups, i.e. ozone-washed and not washed, and stored in ozone-filled cold storage at a dose of 15 gr/m3 per day. Total microbial testing was performed to determine the number of microbes in each vegetable sample. In addition, proximate testing was performed to observe the decreasing rate in nutrient content during storage time. The results showed that ozone-washed tomatoes is the most durable varieties which can stay fresh until day-12 with TPC and YMC values of 4.8x105 CFU/g and 13x105 CFU/g respectively. While the control tomato has a TPC and YMC value of 2.0x106 CFU/g and 85x106 CFU/g respectively. In addition, the proximate test results showed that the nutrient content in each ozone-washed samples didn't decrease significantly compared with the control samples. These results indicate that ozone-washing treatment can extend the shelf life of vegetables while still maintaining their nutritional value.
44
TAUXE, R., H. KRUSE, C. HEDBERG, M. POTTER, J. MADDEN, and K. WACHSMUTH. "Microbial Hazards and Emerging Issues Associated with Produce† A Preliminary Report to the National Advisory Committee on Microbiologic Criteria for Foods." Journal of Food Protection 60, no. 11 (November 1, 1997): 1400–1408. http://dx.doi.org/10.4315/0362-028x-60.11.1400.
Full textAbstract:
In the past two decades, the consumption of fresh fruits and vegetables in the United States has increased, and the geographic sources and distribution of fresh produce have expanded greatly. Concomitantly, public health officials have documented an increase in the number of reported produce-associated foodborne disease outbreaks in the United States. The Centers for Disease Control and Prevention (CDC) reports that the number of these outbreaks doubled between 1973 and 1987, and 1988 and 1991, and that the number of cases of illness associated with these outbreaks more than doubled. A variety of produce items have been affected. During 1995 alone, major outbreak investigations linked infections with Salmonella serotype Stanley to alfalfa sprouts, Salmonella Hartford to unpasteurized orange juice, Shigella spp. to lettuce and green onions, Escherichia coli O157:H7 to lettuce, and hepatitis A virus to tomatoes. In response to this apparent increase, the U.S. Food and Drug Administration asked the National Advisory Committee on Microbiological Criteria for Foods to address and better define the association of foodborne disease and microbial pathogens with fresh produce. A subcommittee formed in June 1995 is documenting relevant epidemiologic data, current industry practices, and laboratory data to identify potential hazards and related control strategies. This report presents the preliminary findings of that subcommittee.
45
BEUCHAT, L. R., B. V. NAIL, B. B. ADLER, and M. R. S. CLAVERO. "Efficacy of Spray Application of Chlorinated Water in Killing Pathogenic Bacteria on Raw Apples, Tomatoes, and Lettuce." Journal of Food Protection 61, no. 10 (October 1, 1998): 1305–11. http://dx.doi.org/10.4315/0362-028x-61.10.1305.
Full textAbstract:
Washing whole and cut produce by dipping or submerging in chlorinated water has a sanitizing effect, although reduction in microbial populations is minimal and is usually less than 100-fold. A study was undertaken to evaluate the efficacy of a spray application of chlorine in killing Salmonella, Escherichia coli O157:H7, Listeria monocytogenes, yeasts and molds, and total aerobic mesophilic microorganisms on whole apples, tomatoes, and lettuce leaves. Inoculated produce was treated (sprayed and then soaked) with water (control) or Solutions containing 200 or 2,000 ppm of chlorine for 0, 1,3, 5, or 10 min, rinsed with sterile water, and analyzed for populations (CFU/cm2) of target microorganisms. Compared to the control treatment, further reductions in numbers of pathogens of 0.35 to 2.30 log CFU/cm2 were achieved by treatment with chlorine. Chlorine was generally more effective at 2,000 ppm than at 200 ppm. Inactivation of microorganisms occurred essentially within 1 min after application of chlorine. These reductions are significant relative to populations of pathogenic microorganisms that may be present on produce. Spray application of chlorine to raw produce at food Service or household levels may be a suitable, and more convenient, alternative to treatment by dipping or submersion.
46
Pieper, Jeffrey R., Rebecca Nelson Brown, and José A. Amador. "Effects of Three Conservation Tillage Strategies on Yields and Soil Health in a Mixed Vegetable Production System." HortScience 50, no. 12 (December 2015): 1770–76. http://dx.doi.org/10.21273/hortsci.50.12.1770.
Full textAbstract:
Most vegetable farms in southern New England market directly to consumers and are characterized by high crop diversity and intensive cultivation. Growers rely on tillage to prepare fields for planting and control weeds, but are concerned about the negative effects of tillage on soil health. This study evaluated three tillage reduction strategies in a market garden system producing tomatoes, melons, cucumbers, cabbage, carrots, and lettuce. Treatments of strip tillage into a killed cereal rye (Secale cereale) cover crop mulch, perennial white clover (Trifolium repens), and ryegrass (Lolium perenne) living mulch between planting rows, and annual crimson clover (Trifolium incarnatum) living mulch interseeded between vegetable rows were established in 2010 and compared over 3 years to a control system using tillage to maintain bare ground between rows. Treatments were evaluated for effects on vegetable yield and soil biological, chemical, and physical properties. The strip tillage treatment was the most effective at promoting soil health, resulting in significant increases in soil aggregate stability, potentially mineralizable nitrogen, active soil carbon, and microbial activity relative to the control, and significant decrease in loss of soil organic matter. However, it was not effective for production of vegetables, with the strip-tillage plots having the lowest yields throughout the study. The perennial living mulch treatment produced yields of carrots, melons, and cucumbers similar to the control yields, but reduced yields of tomatoes, cabbage, and lettuce. Microbial respiration was significantly higher than in the control, and nitrate levels, and loss of soil organic matter were significantly lower. The annual living mulch treatment produced yields similar to the control for all crops, and soil health was similar to the control for all variables except soil nitrate, which was significantly higher than the control. Perennial living mulch shows the most promise for improving soil health while maintaining yields in some vegetable crops, but challenges remain in preventing competition between vegetables and living mulches.
47
YILMAZ, AYSUN, KAMIL BOSTAN, EDA ALTAN, KARLO MURATOGLU, NURI TURAN, DERYA TAN, CHRISTOPHER HELPS, and HUSEYIN YILMAZ. "Investigations on the Frequency of Norovirus Contamination of Ready-to-Eat Food Items in Istanbul, Turkey, by Using Real-Time Reverse Transcription PCR." Journal of Food Protection 74, no. 5 (May 1, 2011): 840–43. http://dx.doi.org/10.4315/0362-028x.jfp-10-475.
Full textAbstract:
Investigation of norovirus (NoV) contamination of food items is important because many outbreaks occur after consumption of contaminated shellfish, vegetables, fruits, and water. The frequency of NoV contamination in food items has not previously been investigated in Turkey. The aim of this study was to investigate the frequency of human NoV genogroups (G) I and II in ready-to-eat tomatoes, parsley, green onion, lettuce, mixed salads, and cracked wheat balls. RNA was extracted with the RNeasy Mini Kit, and a real-time reverse transcription (RT) PCR assay was performed using primers specific for NoV GI and GII. Among the 525 samples analyzed, NoV GII was detected in 1 green onion sample and 1 tomato sample by both SYBR Green and TaqMan real-time RT-PCR assays; no GI virus was detected. The Enterobactericaeae and Escherichia coli levels in the NoV-positive green onion were 6.56 and 1.28 log CFU/g, and those in the tomato were 5.55 and 1.30 log CFU/g, respectively. No significant difference in the bacterial levels was found between the NoV-positive and NoV-negative samples. This study is the first in which NoV GII was found in ready-to-eat food collected from Istanbul, Turkey; thus, these foods may be considered a risk to human health. Epidemiological studies and measures to prevent NoV infection should be considered.
48
WON, GAYEON, PAMELA J. SCHLEGEL, JENNIFER M. SCHROCK, and JEFFREY T. LeJEUNE. "Absence of Direct Association between Coliforms and Escherichia coli in Irrigation Water and on Produce." Journal of Food Protection 76, no. 6 (June 1, 2013): 959–66. http://dx.doi.org/10.4315/0362-028x.jfp-12-512.
Full textAbstract:
Irrigation water is considered a potential source of preharvest pathogen contamination of vegetables. Hence, several organizations have recommended microbiological standards for water used to irrigate edible plants. The purpose of this study was to determine the strength of association between microbial quality indicators (coliforms and Escherichia coli) in irrigation water and on irrigated vegetables. Data analyzed included original results from a cross-sectional study conducted in the Midwestern United States during summer 2009 and information presented in two previously published studies performed in France and Portugal to investigate microbial quality of irrigation water and watered produce. In the cross-sectional study, repetitive PCR (rep-PCR) was used to characterize genetic relatedness of E. coli isolates from water and vegetables. No significant correlations were found between fecal indicators on leafy greens (lettuce and parsley, n = 91) or fruit (tomatoes and green peppers, n = 22) and those found in irrigation water used in the cross-sectional study (P > 0.40) or in the previously published data sets (data set 1: lettuce and waste irrigation water, n = 15, P > 0.40; data set 2: lettuce and irrigation water, n = 32, P = 0.06). Rep-PCR banding patterns of E. coli strains were all distinguishable among the pairs of E. coli isolates recovered from produce and irrigation water on the same farm. From the available data, the concentration of indicator organisms based on a single measure of irrigation water quality was not associated with the presence of these indicators on produce. In the absence of additional information, the use of a single microbial water quality parameter as an indicator of produce safety is of limited value for predicting the safety of the produce.
49
Park, Jaehong, James W. Mjelde, Stephen W. Fuller, Jaime E. Malaga, C. Parr Rosson, and Frank J. Dainello. "An Assessment of the Effects of ENSO Events on Fresh Vegetable and Melon Supplies." HortScience 37, no. 2 (April 2002): 287–91. http://dx.doi.org/10.21273/hortsci.37.2.287.
Full textAbstract:
The historical effects of El Niño/La Niña events on supplies of selected fresh vegetables and melons (Cucumis melo L.) were evaluated by estimating single-equation supply relationships. Economic variables in the estimated equations were, generally, of the correct sign and significant at usual levels. El Niño events had a negative and statistically significant effect on the Texas muskmelon, Florida fall squash [Praecitrullus fistulosus Stocks) Pang.] and the California fall lettuce (Lactuca sativa L.) supply with expected production declines of 15%, 21%, and 5% relative to historical mean production. In contrast, the expected supplies of United States summer onions (Allium cepa L.) and Florida fall and winter tomatoes (Lycopersicon esculentum Mill.) increased about 7%, 10%, and 25% during El Niño events. La Niña events had a negative and significant effect on Texas muskmelon, honeydew, and watermelon, with supplies expected to decline 20%, 29%, and 13% with the occurrence of this event.
50
Poimenidou, Sofia V., Danai-Natalia Chatzithoma, George-John Nychas, and Panagiotis N. Skandamis. "Adaptive Response of Listeria monocytogenes to Heat, Salinity and Low pH, after Habituation on Cherry Tomatoes and Lettuce Leaves." PLOS ONE 11, no. 10 (October 31, 2016): e0165746. http://dx.doi.org/10.1371/journal.pone.0165746.
Full text