Dissertations / Theses on the topic 'Microbial hygiene'

Pathogens on surfaces in child care centers can contribute to illness among attendees and may thereby contribute to medical visits as well. This intervention study was conducted to assess the effect of using specific sanitizing products and cleaning protocols in child care centers on the incidences of lower respiratory infections, diarrheal illness, antibiotic use, and medical visits among children attending the centers and on the levels and antibiotic resistance of indicator bacteria in those centers. During the ten-week study period, children from twelve centers were observed. Six of the centers were randomly assigned to the intervention. The other six were controls. Intervention centers were given cleaning protocols and sanitizing products. Control centers were asked to retain their original procedures and products.Acute illness was determined from records kept by the center directors and telephone calls made to parents of ill children. A call was also made to one randomly selected healthy child's parents for every two ill children recorded. Parents were given a questionnaire requesting information including bedroom sharing status, environmental tobacco smoke exposure, and chronic illnesses.After controlling for within-center clustering and zero-inflation, statistically non-significant trends of reduction were seen in the weeks of lower respiratory infections, diarrheal illness, and medical visits. Multivariable zero-inflated Poisson regression revealed that the number of weeks intervention center children were using antibiotics was 32% lower than among the control center children. This was a statistically significant reduction (95% CI = 0.54-0.86; p = 0.001).Bacterial samples were collected from ten sites within each center at the beginning and the end of the study period to determine the effect of the intervention on the microbial population. The study determined the heterotrophic plate count bacteria numbers and the rates of resistance to ampicillin and cephalothin. Neither heterotrophic bacterial concentrations nor antibiotic resistance rates significantly changed over the course of the study.

Greywater is domestic household wastewater without inputfrom the toilet, i.e. wastewater from sinks, the shower,washing machine and dishwasher in a home. Source separation ofgreywater can be a strategy to enhance recirculation of plantnutrients and/or improve water use. The risk for transmissionof disease when reusing greywater is largely dependent on thecross-contamination by faeces. High levels of faecalindicators, mainly thermotolerant coliform bacteria, have beenreported in greywater, indicating substantial faecal pollution.However, growth of indicator bacteria within the system leadsto an overestimation of thefaecal input and thus the hygienerisk. The faecal input of the greywater in Vibyåsen,Sollentuna, North of Stockholm, was estimated to be 0.04 ±0.02 g faeces person-1 day-1 from the quantification of thefaecal sterol coprostanol, compared to 65 g, 5.2 g and 0.22 gp-1 d-1 using E. coli, enterococci and cholesterolrespectively.

Prevalence of pathogens in the population and the faecalload based on coprostanol concentrations were used to form thebasis of a screening-level quantitative microbial riskassessment (QMRA) that was undertaken for rotavirus, Salmonellatyphimurium, Campylobacter jejuni, Giardia intestinalis andCryptosporidium parvum, looking at the treatment required to bebelow an acceptable level of risk (10-3) for reuse or dischargeof the greywater. The different exposure scenarios simulated–groundwater recharge, direct contact, irrigation andrecreational water–showed that a reduction of 0.7–3.7 log was needed for rotavirus, with the measured level offaecal load in Vibyåsen. The other pathogen of concern wasCampylobacter, where a 2.2 log reduction was needed forgroundwater recharge. The infectious dose of Salmonella is highand the excretion numbers of Giardia cysts and Cryptosporidiumoocysts low, resulting in no treatment requirements for theseorganisms under these circumstances. Pathogen input fromcontaminated food via the kitchen sink had a minor effect onthe microbiological quality of the greywater. Studies on virusoccurrence in greywater as well as validation of the faecalload of greywater at another site would give valuable input forfuture QMRAs.

Greywater treatment efficiency studies, especially on virusremoval, are scarce and more investigations are warranted.Active sludge may not be a suitable technique for greywater dueto the low carbon content in this flow. Chemical precipitationhas the advantage of removing phosphorus as well as virusesefficiently and it is suggested as one possible method fortreating greywater. Otherwise the most common practice forgreywater treatment in Sweden is soil infiltration. However, itis suggested that the recommendations for wastewaterinfiltration also be observed for greywater, despite the lowfaecal load, due to the simulated results on virus reductionneeded.

Key words:greywater, greywater reuse, greywatertreatment, microbial risk assessment, groundwater recharge,irrigation, recreational water, faecal contamination, indicatorbacteria, index organisms, faecal sterols, bacteriophages,enteric pathogens, rotavirus, Salmonella, Campylobacter,Giardia, Cryptosporidium, Legionella

This descriptive study was conducted in the State of Bahrain using: firstly, a questionnaire for students in the final year of their school education, together with a similar questionnaire for their parents, teachers and all Bahraini health promoters; secondly, focus group interviews; thirdly, hazard analyses critical control point (HACCP) model and a checklist to assess schools' canteen, and finally, an evaluation of school's textbooks and health education materials. The study was designed to answer three principal research questions: 1. Do Bahrainis have appropriate knowledge, healthy beliefs and opinions which will empower them to control food poisoning; 2. Are the canteen environments and the practices within the canteens supportive to health; 3. Do school textbooks and health education materials empower the community in food safety? This study describes for the first time the knowledge, attitudes, beliefs of students, parents, teachers, and health promoters in food safety and HACCP in schools and TLMs and linked these three areas to suggest empowering control measures. The results of this study indicate that future health promotion programmes should start at primary school level and teachers need to be further trained in environmental health issues. Canteen environment, and practices need to be further addressed by authorities. Particular attention should be focused on the critical control points which are the time of preparation, transportation, storage and temperature control during display of foods. There is a need for providing appropriate resources which influence learning and community empowerment. Recommendations also suggested the implementation of the Ottawa Charter for Health Promotion which mobilises all the community, resources and the media.

Human excreta contain plant nutrients and have the potentialto be used as a fertiliser in agriculture. Urine contributesthe major proportion of the nutrients (N, P and K) in domesticwastewater whereas faeces contribute a smaller amount andinvolves greater health risks if reused due to the possiblepresence of enteric pathogens. Human urine does not generallycontain pathogens that can be transmitted through theenvironment.

Source-separation of urine and faeces is possible by usingurine-separating (or urine-diverting) toilets, available assimple dry toilets or porcelain flush toilets with dividedbowls. The risk for transmission of disease when handling andreusing the urine is largely dependent on thecross-contamination by faeces. In this research, the presenceof human faeces in urine samples was successfully determined byanalysing for faecal sterols. Cross-contamination was evidentin 22% of the samples from urine collection tanks, and in thesequantified to an average (± SD) of 9.1 ± 5.6 mgfaeces per litre urine. Testing for indicator bacteria wasshown to be an unsuitable method for determining faecalcontamination in human urine sinceE. colihad a rapid inactivation in the urine and faecalstreptococci were found to grow within the system.

The fate of any enteric pathogens present in urine iscrucial for the risk for transmission of infectious diseases.Gram-negative bacteria (e.g.SalmonellaandE. coli) were rapidly inactivated (time for 90%reduction, T₉₀<5 days) in source-separated urine at itsnatural pH-value of 9. Gram-positive faecal streptococci weremore persistent with a T₉₀of approximately 30 days. Clostridia sporenumbers were not reduced at all during 80 days. Similarly,rhesusrotavirus andSalmonella typhimuriumphage 28B were not inactivated inurine at low temperature (5°C), whereas at 20°C theirT₉₀-values were 35 and 71 days, respectively.Cryptosporidiumoocysts were less persistent with a T₉₀of 29 days at 4°C. Factors that affect thepersistence of microorganisms in source-separated human urineinclude temperature, pH, dilution and presence of ammonia.

By using Quantitative Microbial Risk Assessment (QMRA), therisks for bacterial and protozoan infections related tohandling and reuse of urine were calculated to be<10^-3for all exposure routes independent of the urinestorage time and temperature evaluated. The risk for viralinfection was higher, calculated at 0.56 for accidentalingestion of 1 ml of unstored urine. If the urine was stored at20°C for 6 months the risk for viral infection was reducedto 5.4 × 10^-4.

By following recommendations for storage and reuse, whichare dependent on the type of crop to be fertilised, it ispossible to significantly decrease the risk for infections. Sofar, the level of risk that is acceptable is unknown. Theacceptable risk will be one of the main factors determining thefuture utilisation of source-separated human urine inagriculture.

Keywords:urine-separation, urine, wastewater systems,wastewater reuse, recycling, enteric pathogens, faecal sterols,indicator bacteria, hygiene risks, microbial persistence,microbial risk assessment, QMRA, fertiliser, crop.

Thesis (M. Tech. (Environmental Health)) - Central University of Technology, Free State, 2014
In the battle to sustain and produce quality food that is safe and affordable, the limited legislative and regulatory environment continues to allow opportunities for food to become contaminated during processing. The degree of contamination distributed over the final food product (including meat products) depends upon several factors that include knowledge and behaviour of the food handlers, equipment, the hygiene habits of personnel, and the monitoring that takes place at food processing plants (including butcheries). The current study was conducted in five selected butcheries (forming 15% of the registered butcheries at the time the study was conducted) in the Mangaung Metropolitan municipal area, purposely targeting the ones registered with the municipality. The hygiene practices of meat handlers were assessed (through self-administered questionnaires) because meat is a perishable product that requires labour intensive processing for production of quality products. Thus, mishandling by food handlers may create and maintain conditions favourable to microbial contamination. Furthermore, the study assessed and characterised microbial contamination on working surfaces and utensils through swabs as well as bioluminescence instrument [Adenosine Tri-phosphate (ATP) Hygiena] for cleanness of the working environment. Concomitant to the above, meat handlers’ hands and aprons were also assessed for possible microbial contamination as well as their characterisation. Lastly, aerosolised microbes [through an air sampler (Surface Air System) SAS Super 90] were also collected for iv quantification and identification during working hours as airborne microbes can settle on working surfaces and/or utensils as a result of movement of workers and other related working processes. Statistical points such as correlations, standard deviations, group standard deviations as well as significant differences were captured per respective chapter where necessary. Data reported in this study is over 3 month period with two weeks intervals during sampling and thus reported as either weekly or rounds between sampling periods. The results of the current study indicate that the food safety objectives are negligibly achieved, indicating a need for proper food safety training which is audit based. On administration of a questionnaire, food handlers showed poor knowledge of food safety awareness coupled with poor attitude and behaviour in terms of food safety. The five butchery premises were further examined regarding the airborne and surface microbial loads, as well as that of the food handlers’ hands, during processing. The microbial loads in the air appeared to comply with the suggested limits at all the sampled butcheries. Microbial loads on meat contact surfaces showed levels conforming to the South African standard or guideline of 1 × 102 cfu.m-2. Total Coliforms on hands and on aprons were compared to the general microbial target value of <2.5 cfu.m-2 as suggested by literature. In this study, Matrix Laser Desorption Time of Flight Mass Spectrophotometer (MALDI-TOF MS) was found to be an accurate, rapid and cost effective method towards v identifying of foodborne pathogens and spoilage bacteria including yeast. Moreover, in recent years South Africa’s meat scandals have increased consumer awareness and the demand for food safety. Section 11 of the Meat Safety Act (Act no. 40 of 2000) stipulates that every abattoir must utilize an independent inspection service appointed by the department of agriculture to ensure that meat of high quality and wholesomeness is produced. However, once the meat and meat products leave the abattoir, they are under the jurisdiction of the local authorities who rely only on visual assessment as opposed to microbiological inspection in the maintenance of their hygiene and quality. Despite the high incidence of foodborne illnesses in both developed and developing countries; South African data on foodborne illness incidents is still insufficient. This could be attributed to the fact that in South Africa, legislation governing the acceptable standards of the levels of microbiota in the air and on food handlers’ hands is still inadequate. Additionally, lack of obligatory usage of Hazard Analysis Critical Control Point (HACCP) procedures in the meat premises poses a risk for economic productivity. In conclusion, the identification of airborne bacteria in the butcheries strongly suggests that in the planning of the existing establishments, the building layout, control of the traffic flow of personnel, the durability and imperviousness of floors, the ventilation system and the placement of the equipment were not carefully considered. This may play a role in the prevalence and proliferation of airborne microbes as the resulting establishments provide an environment conducive to the breeding of microbes. vi In regard to swabs, it was concluded that floors may present a high point of contamination possibly through aerosolization of microbial communities. Moreover, cleaning materials and hygiene practices need to be reviewed. The results of the administered questionnaire showed that food handlers should be sufficiently trained with regard to food quality management tools such as Good Manufacturing Practices (GMP), Hazard Analysis and Critical Control Point (HACCP) systems and food safety. The evaluation of meat contact surfaces for organic soils to determine their cleanliness using the rapid ATP bioluminescence testing can be convenient for everyone involved in the food chain since visual and touch inspection cannot be conclusive enough to meet regulatory requirements in terms of microbial counts.

Dissertação de Mestrado Integrado em Medicina Veterinária
Insect consumption has been increasing worldwide, particularly in industrialized countries. Insect-based ingredients are considered novel foods in Europe, which raises some concern regarding the food safety of these products. Gut emptying by starvation prior to killing is perceived as an effective practice in the reduction of the microbial load of insects but can lead to weight loss and consequently a profit reduction to the farmers. The purpose of this study was to evaluate the fat loss of crickets (Acheta domesticus) starved for 0h, 24h and 48h, and their corresponding microbial loads (total aerobic counts (TAC) and Enterobacteriaceae). Gram stains were also performed for the colony-forming units (CFU) from TAC. The effect of sex on the microbial numbers was assessed, having not been found significant differences (p=0.72 and p=0.46 for TAC and Enterobacteriaceae, respectively). TAC increased (p=0.002) by almost 1 log CFU/g in the 48h starvation group. Only the 24h starvation group showed a significant decrease (p=0.004) in Enterobacteriaceae counts of 1 log CFU/g. The Gram stains showed changes in the microbiological composition of samples collected at 24 and 48h. Gram-positive cocci predominated at 24h but decreased at 48h (from 68 to 48%). Bacilli were only detected at 24h (8%). The fat content did not decrease significantly, neither at 24h (p=0.13 for males and p=0.13 for females) nor at 48h (p=0.57 and p=0.98 for males and females, respectively). Starvation for 24h was efficient in reducing the microbial load of raw crickets without significant fat loss. A longer starvation period promoted a higher microbial load, possibly due to modulation observed in the microbial diversity.
RESUMO - Impacto do jejum na matéria gorda e teor microbiano presente no grilo doméstico (Acheta domesticus) utilizado para alimentação humana - O consumo de insetos tem vindo a aumentar globalmente, particularmente em países industrializados. Ingredientes à base de insetos são considerados novos alimentos na Europa, o que suscita alguma preocupação em matéria de segurança dos alimentos destes ingredientes. O esvaziamento do trato gastrointestinal através de jejum antes do abate é visto como uma prática eficaz na redução do teor microbiano presente nos insetos, mas pode, no entanto, levar a perda de peso considerável e, consequentemente, à redução de lucro para os produtores. O objetivo deste estudo foi avaliar a perda de gordura no grilo doméstico (Acheta domesticus) quando submetido a períodos de jejum de 0h, 24h e 48h, e correspondentes teores microbianos (Aeróbios totais (AT) e Enterobacteriaceae). Foram ainda feitas colorações de Gram a partir das unidades formadoras de colónia (UFC) das placas de AT. O efeito do sexo na carga microbiana foi avaliado, não tendo sido encontradas diferenças significativas (p=0.72 e p=0.46 para AT e Enterobacteriaceae, respetivamente). A contagem de AT aumentou (p=0.002) em cerca de 1 log UFC/g no grupo de jejum de 48h. Apenas o grupo submetido a jejum por 24h mostrou um decréscimo significativo (p=0.004) nas contagens de Enterobacteriaceae na ordem de 1 log UFC/g. As colorações de Gram mostraram alteração da composição microbiana das amostras colhidas às 24 e às 48h, com predominância de cocos Gram-positivos às 24h e redução às 48h (de 68 para 48%). Foram detetados bacilos apenas no grupo 24h (8%). Não houve redução significativa do teor de gordura nem às 24h (p=0.13 em machos e p=0.13 em fêmeas) nem às 48h (p=0.57 e p=0.98 em machos e em fêmeas, respetivamente). A aplicação de um período de jejum de 24h foi eficaz na redução da carga microbiana de grilos crus sem redução de gordura significativa. Um período de jejum mais prolongado promoveu um teor microbiano mais elevado, possivelmente devido à modulação da diversidade microbiana.
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A presente investigação teve como objetivo avaliar a prática de cirurgiões dentistas em uma unidade de terapia intensiva (UTI) de um hospital militar, o estabelecimento de um protocolo de higiene oral e os seus efeitos sobre a redução de pneumonias associadas à ventilação mecânica (PAVM). As percepções da equipe da UTI sobre as atividades dos cirurgiões dentistas também foram avaliadas por meio de um questionário. O perfil de colonização microbiana da mucosa oral antes e depois do estabelecimento das medidas de higiene oral também foi avaliado tanto por diluição e plaqueamento em meios de cultura microbiológicos seletivos e enriquecidos e através da amplificação pelo método de PCR e eletroforese em gel desnaturante em gradiente (DGGE), subsequente ao sequenciamento dos amplicons. A carga microbiana foi avaliada após a contagem de placas de agar e através da amplificação por PCR em tempo real (qPCR) do gene rrs nas amostras. O protocolo de higiene oral, realizado pelos cirurgiões dentistas, foi capaz de reduzir a incidência de PAVM (p <0,05). O questionário revelou que a modificação da halitose foi percebida por 93,33% dos participantes. A redução da ocorrência das úlceras orais e dos lábios durante a internação dos pacientes foi observada por 80% da equipe da UTI. Foi observada a redução da produção das secreções nasais e bucais por 70% da equipe dos profissionais da UTI. Para 86,66% dos participantes a assistência aos pacientes tornou-se mais agradável após a instituição dos cuidados bucais. O protocolo, realizado com a utilização de solução 0,12% de clorexidina, não foi capaz de evitar a colonização da mucosa oral por patógenos microbianos usualmente encontrados no ambiente hospitalar tais como os bastonetes Gram-negativos entéricos e não fermentadores, nem foi capaz de eliminá-los quando tais micro-organismos já se encontravam presentes antes dos procedimentos de higiene bucal. Alguns Bastonetes Gram-positivos (Lactobacillus sp e corinebactérias) e Staphylococcus epidermidis permaneceram após a realização dos procedimentos. O protocolo de higiene oral permitiu a redução da carga microbiana na mucosa oral de 50% dos pacientes considerando-se o método de contagem microbiana e para 35% dos pacientes pela avaliação dos números de cópias de genes rrs através de qPCR. Em conclusão, o protocolo de higiene oral desenvolvido pelos cirurgiões dentistas foi capaz de reduzir a incidência de PAV na UTI, embora não tenha sido capaz de prevenir a colonização da mucosa oral por supostos patógenos microbianos. O protocolo de higiene oral com a participação ativa dos cirurgiões dentistas foi bem aceito pelos profissionais da UTI e foi capaz de melhorar a qualidade da assistência aos pacientes críticos.
This investigation aimed to evaluate the practice of dentists in an intensive care unit (ICU) of a military hospital, the establishment of a protocol for oral hygiene, and the effect of the protocol on the reduction of ventilator associated pneumonia (VAP) after the introduction of the oral hygiene protocol. The opinion of the ICU staff about the activity of the dentists was also evaluated by means of a questionnaire. In addition, the microbial colonization profile of the oral mucosa before and after the establishment of the oral hygiene measures was evaluated by means of both dilution and plating the samples in microbiological culture mediums (both selective and rich agar media) and DGGE technique, with sequencing of amplicons. The microbial load was evaluated after counting agar plates and by real time rrs gene PCR amplification (qPCR) in the samples. The oral hygiene protocol performed by dentists was capable to reduce the incidence of VAP (p< 0.05). The questionnaire revealed that the change of the oral odor was noticed by 93.33% of the participants. The reduction of oral and lip ulcers during the hospitalization of the patients was observed by 80% of the staff. The patients were observed to reduce the production of oral and nasal secretions after the establishment of the oral hygiene procedures by 70% of the ICU professionals. The approach to the patients developed by the staff became more pleasant after the establishment of the oral protocol for 86.66%. The protocol, with the use of 0,12% chlorhexidine solution, was not capable to avoid the colonization of the oral mucosa by the microbial pathogens usually found in nosocomial environment, in especial Gram-negative enteric and non-fermentative rods, nor eliminated these organisms previously found before the oral care procedures. Gram-positive rods (Lactobacillus sp, and corynebacteria) and Staphylococcus epidermidis remained after the procedures. The protocol reduced the microbial load in the oral mucosa of 50% of the patients considering the microbial counting and in 35% of the patients evaluated by the numbers of copies of rrs genes by qPCR. In conclusion, the oral hygiene protocol developed by dentists was capable to reduce the incidence of VAP in the studied ICU, though was not capable to prevent the colonization of oral mucosa by putative microbial pathogens. The oral hygiene protocol with active participation of dentists was well accepted by the ICU professionals and was capable to improve the quality of assistance to critically ill patients.

Thesis (MTech (Biomedical Sciences))--Cape Peninsula University of Technology, 2015.
BACKGROUND AND OBJECTIVES: Group B Streptococci (GBS) can asymptomatically colonise the vagina and rectum of women. Studies have shown that this bacterium is the leading cause of septicemia, meningitis and pneumonia in neonates. In Namibia no known studies have investigated GBS colonisation and the antibiotic resistance profile of GBS isolates in pregnant women. This study accessed the GBS colonisation rate amongst the pregnant women who attended the Windhoek Central Hospital Antenatal Clinic (Khomas region), in Namibia for a period of 13 months. Furthermore, using the VITEK 2 system, the GBS isolates were tested against the following antimicrobial substances; benzylpenicillin, ampicillin, clindamycin, erythromycin, tetracycline, vancomycin, cefotaxime, ceftriaxone, linezolid and trimethoprim/sulfamethoxazole. Penicillin G is the drug of choice in the majority of studies, and seems to be the most effective drug for intrapartum antibiotic prophylaxis (IAP). All the GBS isolates found in this study were also analysed for the presence of selected genes known to be associated with resistance to key antibiotics using specific primers within a polymerase chain reaction (PCR).

U radu je ispitan i razvijen novi pristup tretmanu kože goveda prirodnom smolom šelak, koja je dozvoljena za korišćenje u hrani, u cilju redukcije unakrsne mikrobiološke kontaminacije sa kože na goveđe meso. Mehanizam ovog tretmana je baziran na imobilizaciji mikroorganizama na dlaci tretirane kože i prevenciji njihovog fizičkog prenosa sa dlake na meso trupova tokom procesa obrade zaklanih goveda.U in vitro uslovima, tretman uzoraka vizuelno čiste i suve kože 23% rastvorom šelaka u etanolu je redukovao prenos sa kože na sunđere kojima je koža uzorkovana brisevima: ukupne mikroflore (TVC) za 6,6 log (>1000 puta više u odnosu na 2,9 log redukcije kod tretmana samo etanolom), generičke Escherichia coli za najmanje 2,9 i Enterobacteriaceae za najmanje 4,8 log. Ove redukcije sve tri grupe mikroorganizama su bile značajno više u odnosu na redukcije postignute tretmanom kože kombinacijom ispiranja sanitajzerom i vakumiranja. Značajno više redukcije prenosa TVC sa kože na sunđerske briseve su postignute korišćenjem viših koncentracija šelaka (23% i 30%) u odnosu na niže (4,8-16,7%) i u slučajevima kada je temperatura rastvora šelaka bila 20, 30 ili 40oC u odnosu na 50oC i 60oC. Takođe, tretman kože šelakom je značajno (3,7 puta) redukovao prevalencu E. coli O157 na prirodno kontaminiranoj, neinokulisanoj koži, kao i broj E. coli O157 na veštački inokulisanim kožama (redukcija od 2,1 log), u odnosu na odgovarajuće netretirane kontrole.U uslovima laboratorijskog modela direktnog kontakta kože i mesa, tretman kože (različitih kategorija čistoće) 23% rastvorom šelaka je značajno smanjio prenos mikroorganizama sa tretirane kože na sterilno goveđe meso: do 3,6 log cfu/cm2 redukcije ukupnog broja bakterija (TVC), do 2,5 log cfu/cm2 Enterobacteriaceae (EC) i do 1,7 log cfu/cm2 generičke E. coli (GEC). Redukcija prenosa TVC je bila značajno viša, a redukcije EC i GEC slične, u odnosu na redukcije nakon tretiranja kože kombinacijom ispiranja-vakumiranja sanitajzerom.U uslovima male komercijalne klanice sa nezadovoljavajućom procesnom praksom (klanje prljavih goveda i neadekvatna higijena procesa klanja i obrade), tretman koža zaklanih goveda 23% rastvorom šelaka je rezultirao značajnom mikrobnom redukcijom na mesu trupova goveda nakon skidanja kože: 1,7 log cfu/cm2 TVC, 1,4 log cfu/cm2 EC i 1,3 log cfu/cm2 GEC. Redukcija TVC na mesu trupova je bila značajno viša, a redukcije EC i GEC slične, u odnosu na redukcije nakon tretiranja kože ispiranjem-vakumiranjem sanitajzerom.Ova istraživanja su po prvi put pružila naučne dokaze da se tretman kože goveda u cilju imobilizacije mikroflore na dlaci može uspešno koristiti u cilju smanjenja kontaminacije mesa trupova tokom procesa skidanja kože, unapređenja finalnog mikrobiološkog statusa mesa i bezbednosti goveđeg mesa uopšte. Da bi se ostvario puni potencijal ovog novog tretmana u praksi, neophodna su dalja istraživanja u cilju njegove tehničke optimizacije u uslovima industrije mesa.
In this research, a new approach to cattle hide treatments, based on using a natural, food-grade resin, Shellac, to reduce microbial cross-contamination from the hides onto carcass meat, was developed and evaluated. The basis of this treatment is immobilisation of microorganisms on cattle hide’s hair and subsequent reduction of their transmissibility from the hair onto carcass meat during dressing of slaughtered cattle. Under in vitro conditions, treatment of samples of visually clean and dry hides with 23% Shellac-in-ethanol solution reduced sponge-swabbing recoveries of general microflora (TVC) by a factor of 6.6 logs (>1000-fold greater than the 2.9 log reduction observed by ethanol alone), and of generic E. coli (GEC) and Enterobacteriaceae (EC) by factors of at least 2.9 and 4.8 logs, respectively. The reductions of these three groups of microorganisms were superior to those achieved by a sanitizer rinse-vacuum hide treatment. Significantly greater reductions of TVC recoveries from hides were achieved when using higher Shellac concentrations (23.0% and 30.0% rather than 4.8-16.7%) and when Shellac solution temperatures were 20-40°C rather than 50-60°C. Furthermore, the Shellac-based treatment also markedly reduced the E. coli O157 prevalence (3.7-fold reduction) on natural, uninoculated hides, as well as the counts of E. coli O157 on artificially inoculated hides (2.1 log reduction) when compared to corresponding untreated controls. Under the conditions of a hide-to-meat direct contact laboratory-based model, treatment of hides (of varying visual cleanliness) with the 23% Shellac solution produced significant reductions of microbial transfer from treated hide onto sterile beef: up to 3.6 log10 CFU/cm2 of TVC, up to 2.5 log10 CFU/cm2 of EC and up to 1.7 log10 CFU/cm2 of GEC. TVC reductions of microbial transfer from treated hide onto beef achieved by the Shellac hide treatment were superior to those achieved by the comparative sanitizer rinse-vacuum hide treatment, but reductions of EC and GEC did not differ between the two hide treatments. In a small commercial abattoir with unsatisfactory process practices (slaughtering dirty cattle, inadequate process hygiene), treatment of hides with Shellac produced significant microbial reductions on skinned beef carcasses: 1.7 log10 CFU/cm2, 1.4 log10 CFU/cm2 and 1.3 log10 CFU/cm2 of TVC, EC and GEC, respectively. TVC reductions on skinned beef carcasses achieved by the Shellac hide treatment were superior to those achieved by the comparative sanitizer rinse-vacuum hide treatment, but reductions of EC and GEC did not differ significantly between the two hide treatments. These investigations produced the first scientific evidence that treatment of cattle hides with aim of immobilising microflora on the hair can be very successfully used to reduce carcass meat contamination during the skinning operation, thus improving the microbiological status of the final beef carcasses as well as the beef safety in general. To achieve the full potential of this new treatment in practice, further research aimed at its further technical optimization under real-life meat industry conditions is necessary.

The most common disease causing elements in feed is of microbial nature. Therefore it is of great importance for horse owners to be familiar with the fundamental requirements for microbial growth in feeds and the problems that can originate in case of insufficient handling. However, horse owners are not organized in a way that makes it easy to reach them with information as a target group. Additionally, most horse owners only have one horse and limited possibilities for education in feed safety. Thus, there is need for an easy accessed education material that is explicitly directed towards horse owners. The fundamental content of such an education material was composed in this project. Focus was on the importance of good microbial quality in horse feed and the material was structured into three chapters; FEED SAFETY, MICROORGANISMS IN FEEDS and CONSERVATION, STORING AND FEEDING. The aim was to publish the material as part of a larger web based education package on the web page, http://www.sva.se of the Swedish National Veterinary Institute. The basic structure for such a web education was also composed in this project.

Objectifs L'objectif de la thèse est de caractériser par PCR quantitative en temps réel (QPCR) l'environnement fongique, bactérien ainsi que l'exposition à d'autres organismes allergisants (acariens et animaux de compagnie). Cette caractérisation des logements a pour but de mieux comprendre les interactions entre les différents micro-organismes de l'environnement intérieur et leurs relations aux maladies allergiques, dans le cadre d'une étude de grande cohorte. L'objectif secondaire est la mise en place de nouvelles QPCR dans d'autres circonstances sanitaires (infections, PHS) afin de mieux caractériser l'impact des microorganismes de l'environnement. L'étude EBRA-ELFE L'étude ELFE incluant 18 319 enfants est la première cohorte française qui s'intéresse au développement des enfants de la naissance à leur majorité dans une approche multi­disciplinaire. Une étude nichée EBRA (Environnement microBiologique et Risque Allergique) est centrée sur l'étude microbiologique des poussières dans les chambres d'enfant. Le mode d'échantillonnage (par capteur électrostatique à poussière, EDC) et d'analyse (QPCR) ont été validés et optimisés pour garantir l'acceptabilité du dispositif et la qualité des quantifications. Un panel de 10 cibles (moisissures, acariens, bactéries) sélectionnées pour leur caractère allergisant, toxique, infectieux ou potentiellement protecteur vis-à-vis des maladies allergiques a été initialement utilisé. Ainsi lors de la première collecte à la naissance des enfants en 2011, 3217 CEP ont été quantifiés par QPCR. Les concentrations de six moisissures (Aspergillus fumigatus, Aspergillus versicolor, Alternaria alternata, Cladosporium sphaerospermum, Penicillium chrysogenum, Stachybotrys chartarum), trois groupes de bactéries (Enterobacteriaceae, Mycobacteria et Streptomyces) et un acarien (Dermatophagoïdes pteronissynus) de l'environnement immédiat du nouveau-né ont été obtenues. Ces données ont permis d'identifier six profils de logements différents avec un gradient géographique E-O recouvrant la distribution des sifflements de l'asthme en France. Un deuxième panel de 10 cibles a été choisi et documenté. Il inclut entre autres des cibles « chien » et « chat » pour proposer un test complet comprenant les allergènes principaux des logements. La collaboration avec le groupe ELFE continue et un projet pour une deuxième campagne d'échantillonnage à 5 ans se met en place. L'utilisation de la QPCR pour caractériser d'autres situations à risque. La QPCR est un outil de quantification standardisé et reproductible et ses applications sont multiples. Au cours de ce travail de thèse, elle a été utilisée pour caractériser d'autres situations à risque : quantifier la présence de Thermoactinomyces vulgaris dans les aérosols des stations de compostages, détecter la présence d'Aspergillus fumigatus dans des environnements pouvant recevoir des patients immunodéprimés, mettre en évidence la présence d'ADN d' Aspergillus fumigatus ou de mucorales dans le sérum de patients immunodéprimés. Conclusion Les outils développés et les résultats obtenus pendant la thèse représentent une avancée pour une meilleure connaissance du monde microbien qui nous entoure et contribueront à mieux comprendre les mécanismes de développement des maladies allergiques
Objectives The aim of the study is to characterize by quantitative real-time PCR (QPCR) fungal, bacterial environment as well as exposure to other allergenic organisms (mites and pets). This characterization of dwellings aims to better understand the interactions between the different micro-organisms of the indoor environment and their relation to allergie diseases. The secondary aim is the use of other QPCRs in other health circumstances (infections, ABPA) te better characterize the impact of environmental microorganisms. The EBRA-ELFE study The ELFE study, which includes 18,319 children, is the first French cohort to study the development of children from birth to majority in a multi-disciplinary approach. A nested study EBRA (MicroBiological Environment and Allergie Risk) focuses on the microbiological compositior of dust in children's rooms. The electrostatic dust collector (EDC) sampling and analysis mode has been validated to guarantee an acceptable system (in terms of cost and constraints for the participants) and to optimize the quality of QPCR quantification. A panel of 10 targets (molds, mites, bacteria) selected for their allergenic, taxie, infectious or potentially protective effect against allergie diseases was initially used. Thus during the first sampling at birth of children in 2011, 3217 EDC were quantified by QPCR. The concentrations of six molds (Aspergillus fumigatus, Aspergillus versicolor, Alternaria alternata, Cladosporium sphaerospermum, Penicillium chrysogenum, Stachybotrys chartarum), three groups of bacteria (Enterobacteriaceae, Mycobacteria and Streptomyces) and one mite (Dermatophagoides pteronissynus) of the immediate environment of the new have been obtained. These data made it possible to identify six different dwelling profiles A second panel of 10 targets was chosen and documented. It includes "dog" and "cat" targets te propose a complete test including the main allergens of the dwellings. The collaboration with thE ELFE group continues and a project for a second 5-year sampling campaign is set up.The use of QPCR for the use of QPCR other risk situations The QPCR is a standardized tool, reproducible, allowing quantification and its applications are multiple. During this work, it was used to characterize other risk situations: presence of Thermoactinomyces vulgaris in the aerosols of composting stations, presence of Aspergillus fumigatus in environments that could receive immunocompromised patients , the presence of Aspergillus fumigatus DNA or mucorales in the serum of immunocompromised patients. Conclusion Tools developed and the results obtained during the study represent a step forward for a better knowledge of the microbial envrionnement and will contribute to a better understanding of the mechanisms of development of allergie diseases

La contamination microbienne des units de soins dentaires (USD) est connue depuis les années 60. L'eau circule à l'intérieur des USD dans des conditions favorables au développement d'un biofilm (faible débit, nature des surfaces, stagnation). Ce biofilm, réservoir de micro-organismes potentiellement pathogènes, peut représenter un risque infectieux pour les patients et le personnel dentaire exposés à l'eau et aux aérosols générés lors des soins dentaires, en particulier s'ils sont immunodéprimés.Des micro-organismes provenant de l'eau, tels que les amibes libres, peuvent être retrouvés dans ce biofilm. Des protozoaires ubiquitaires de l'environnement du genre Acanthamoeba ou Hartmannella, connus comme pathogènes opportunistes chez l'Homme (kératites, méningo-encéphalites) et ayant la capacité de servir d'hôte pour le développement intracellulaire de certains microorganismes pathogènes (ex : Legionella pneumophila), ont en effet été isolés dans l'eau des USD.D'autre part, des micro-organismes provenant de la cavité buccale d'un patient peuvent également se retrouver dans le système d'eau des USD, en même temps que des traces de salive et/ou de sang, suite à un dysfonctionnement ou un mauvais entretien des valves anti-reflux des porte-instruments rotatifs. Les levures du genre Candida sont des commensaux du tube digestif humain, pathogènes opportunistes notamment responsables d'infections oro-pharyngées, et parfois retrouvées dans les USD.Ce travail a consisté d'une part en l'étude de la capacité de deux amibes libres : A. castellanii et H. vermiformis, ainsi que de trois espèces de Candida : C. albicans, C. glabrata et C. parapsilosis, à survivre dans l'eau, en présence ou non de salive. Les résultats montrent une influence dose-dépendante et espèce-dépendante de la salive sur la survie des trois levures, et aucun effet sur la viabilité des amibes. Des interactions ont pu être mises en évidence entre amibes libres et levures : A. castellanii est capable d'internaliser puis de digérer les trois espèces de levures, induisant leur élimination rapide, indépendamment de la présence de salive. En revanche, H. vermiformis permet la survie et la prolifération de Candida spp. dans l'eau, même en l'absence de salive.Enfin, dans une démarche de prévention et de lutte contre le risque infectieux lié à l'eau des USD, l'efficacité de différents traitements chimiques communément utilisés : le chlore (NaOCl), le peroxyde d'hydrogène (H2O2) et l'Oxygenal 6©, a été étudiée sur les différentes espèces de Candida et d'amibes libres. Ces traitements montrent une efficacité variable : le chlore requiert l'utilisation de concentrations élevées (>26 ppm) et peu compatibles avec l'usage courant des USD. Le H2O2 ne présente pas d'activité significative dans les conditions testées (de 0.07% à 0.9% v/v). En revanche, l'Oxygenal 6© apparaît le plus efficace pour l'éradication des levures du genre Candida et des amibes libres dans l'eau (dès 0.05%)
Microbial contamination of dental unit waterlines (DUW) is known since the 60's. Water circulates throughout DUW with environmental conditions encouraging biofilm development (low flow, surface material, stagnation). This biofilm, which is a reservoir of potentially pathogenic micro-organisms, may represent an infectious risk for patients and dental staff exposed to water and aerosols generated during dental cares, in particular for immunocompromised persons. Micro-organisms coming from water, such as free-living amoebae (FLA), may be isolated in this biofilm. Protozoa belonging to Acanthamoeba or Hartmannella genera are ubiquitous in the environment; they are known to be opportunistic pathogens for Human (keratitis, meningo-encephalitis), to encourage intracellular development of some pathogenic micro-organisms (for example: Legionella pneumophila), and they have already been isolated in DUW.On the other hand, micro-organisms coming from the oral cavity of an infected patient may also be isolated in DUW water, mixed with saliva traces and/or blood, mainly because of the dysfunction or the poor maintenance of anti-retraction valves. Candida yeasts colonize human's oral cavity and digestive tract as commensals or opportunistic pathogens, thus implicated in oro-pharyngeal infections; they are sometimes isolated in DUW.This work focused first on the study of the survival capacity of two species of FLA: A. castellanii and H. vermiformis, and three species of yeasts: C. albicans, C. glabrata and C. parapsilosis, in water, with or without saliva. Results showed that the addition of saliva permitted both survival and proliferation of all three tested Candida species whereas no effect was observed on FLA growth. Then, interactions have been demonstrated between FLA and yeasts: A. castellanii were able to internalize and then digest the three tested yeasts species, inducing their rapid degradation, independently of saliva presence. Conversely, H. vermiformis were able to promote Candida survival and proliferation in water, with or without saliva.Finally, in order to prevent and fight against infectious risk associated with DUW water, the efficacy of commonly used chemical treatments: chlorine (NaOCl), hydrogen peroxide (H2O2) and Oxygenal 6©, was studied against the three species of Candida and the two species of FLA. These treatments showed a variable efficacy: chlorine was effective only using the highest tested concentrations (> 14 ppm), which are not compatibles with DUW use. H2O2 displayed no significant activity in the experimental conditions (0.07% to 0.9% v/v). Oxygenal 6© seemed to be the more effective for eradication of Candida yeasts and FLA, in water (even with 0.05% v/v)

Fermentation is a process by which primary food products are modified biochemically by the action of microorganisms and/or their enzymes. Several societies have, over the years, intentionally carried it out to enhance the taste, aroma, shelf-life, texture, nutritional value and other properties of food. It is used in many parts (lithe world. However, there are regional differences in use and these depend on the availability of raw materials, consumption habits. and other socio-cultural factors. This study was aimed at (comparatively) assessing, local commercial and homemade amahewu with respect to nutritional value, hygiene and other health benefits to the commirn ity. Methods employed were Thin Layer Chromatography (TLC) (mycotoxins), High Perliffmance Liquid Chromatography (HPLC) (mycotoxins, sugars and amino acids), Dumas (proteins), SOxhlet (lipids) and intubation technique (metabolisable energy) to analyse maize meal and amahewu samples from various regions. The regions sampled included mal3heleni (South Coast) and kwaNgcolosi (North Coast) villages. Commercial amahewu was analysed with kind permission from Clover SA. Species from the following genera were isolated and identified from amahewu samples: Lactobacillus, Saccharonivccs, Lcuconostoc, Lactococcus, Panioca, Entcrobacter and kleb•iella. Saccharotnyces was detected in commercial samples only. Gram-negative strains were identified in most of manheleni village samples. No traceable amounts of aflatoxin BI (AFB1), fumonisin B 1 (FBI) and zearalenone (ZEA) were found in Clover SA samples. AFB I was detected in 40% of both maize meal and amahewu samples from maBheleni (range 0.55 — 0.84ng/g and 8.3x10 5 — 9.1x10-5ng/g respectively). From the same village, 100% of the maize meal and 80% of the amahewu samples were contaminated with FBI (range 4.1 47.2ng/g and 1.4 ---- 6.9ng/g respectively). ZEA was detected in all maize meal samples (range 0.9 — 4.3ng/g). None of the amahewu samples contained detectable levels of ZEA. All maize meal and amahewu samples from kwaNgcolosi were contaminated with AF13 1 (range 8.3 — 30.I ng/g and 0.04 - 0.102ng/g respectively). FB I was detected in 75% of both maize meal and amahewu samples from the same village (range 0.5 — 4.1ng/g and 0.04 0.56ng/g respectively). ZEA was also found in all maize meal samples and 75% of amahewu samples (range 3.7 — 16.4ng/g and 0.03 -- 0.06ng/g respectively). MaBheleni, Clover SA and kwaNgcolosi maize meal and amahewu samples contained vitamins B1, 13 2 and B6 with a range of 0.31+0.21 - 4.48±0.81 B 1 ; 0.15±0.14 - 1.67±0.33 B2 and 0.05±0.07 - 0.77±1.45 lig/g B6. Fat levels ranged from 0.28±0.40 to 4.54±0.05 percentage by weight. The levels of proteins varied from 4.02±0.02 to 8.40±0.04 percentage by weight. Starch concentrations ranged from 31.51.5.28 to 75.911.92g/100g. Maize meal samples contained glucose and maltose, while glucose, fructose, sucrose, maltose, M-triose, DP 4 and 5 and DP >15 were detected in amahewu. Apparent and true metabolisable energy for homemade and commercial Freeze-dried amahewu was 13.194 and 13.696MJ/kg (AME N ); and 13.605 and 14.106M.Ekv ( 1 MEN ), respectively. This study has shown that lactic acid maize fermentation reduce' the levels of AF13 1 , FB I and ZEA toxins in maize meal, inhibits the growth of most Gram-negative bacteria, and in some instances, fermentation did improve the nutritional value. Metabolisable energy analysis represents an important tool to assess whether or not compounds ingested are converted to sources of energy in the body and utilised. Amahewu fermentation yielded beneficial products (probiotics: reduced mycotoxins levels and reduced starch). In conclusion, natural lactic acid maize fermentation to produce amahewu will do more good than harm to the consumer, therefore, people need to be advised on how to safely store their maize and also to be encouraged to consume their stored maize in fermented form.
Thesis (M.Med.Sc.)-University of Natal, Durban, 2003.

Due to the intrauterine environment required to maintain pregnancy it may be that neonatal animals are born type-2 immune response (IR) biased, which consequently may increase susceptibility to certain infectious and immune mediated diseases, such as allergy. Recently, the prevalence of both allergic and autoimmune diseases has increased, leading to the development of the hygiene hypothesis. The hypothesis states that lack of early environmental stimulus leading to inappropriate development and bias in IR, may contribute to this increase. The objectives of this thesis, therefore, were to: (a) Determine the IR bias of neonatal pigs. (b) Investigate the effect of heat-killed Escherichia coli, lipopolysaccharide (LPS) and muramyl dipeptide (MDP) on the IR phenotype and the frequency of allergy in pigs sensitized to the egg white allergen ovomucoid (Ovm). (c) Establish IR phenotypes of pigs allergic or clinically tolerant to Ovm. Immune response bias was determined using an established phenotyping protocol and compared between two groups of pigs, (A) and (B). A difference in IR bias was observed. Bias in IR was not consistently towards type-2. Increase in indicators of type-1 IR, were greater in A and the frequency of type-2 IR correlates were greater in B. It’s likely that unidentified environmental variables may have induced this change, although etiology was not pursued. Treatment with heat-killed Escherichia coli, LPS and MDP had an effect on IR bias and frequency of allergy. Muramyl dipeptide-treatments promoted type-2 bias and were associated with increased frequency of allergy. Pre-treatment with E. coli did not affect allergic frequency, but did elicit the production of a relatively balanced allergen-specific IR phenotype. Lipopolysaccharide-pre-treatment was associated with decreased frequency of allergy. Correlates of an allergic IR phenotype in pigs were also established. The measurement of allergen-specific IgG, IgG1 and/or IgE activity and evaluation of late-phase intradermal skin tests were proposed to be useful in identifying allergic IR phenotypes. This thesis emphasizes the importance of considering the potential for variation in IR in terms of pig health and experimental reproducibility. Further, given the physiological similarities of pigs and humans, these findings may be extended to studies of food allergy in humans.
NSERC, OMAFRA, Ontario Pork, AllerGen NCE

The aim of this study was to investigate the microbiological quality of drinking water at the source (taps at eThekwini laboratories, standpipes and mobile community tankers) and corresponding point-of-use (storage containers and ground tanks) supplied to peri-urban areas in Durban by eThekwini Municipality. It also aimed to identify factors associated with deterioration in water quality such as storage of water, household demographics, hygiene and sanitation practices. In order to determine the microbial quality of drinking water, the pour plate method (for enumeration of heterotrophic organisms) and the membrane filtration technique (for total coliforms and E. coli enumeration) were used. Conductivity, turbidity, pH and total and residual chlorine levels of drinking water were measured. Microbial and physico-chemical data was collated and statistically analysed with epidemiological data from an associated study to determine the link between microbial quality of drinking water, household demographics, health outcomes, socio-economic status, hygiene and sanitation practices. Findings showed that all point-of-use water was unsafe for human consumption as a result of either poor source water quality, in the case of standpipes, and microbial contamination at the point-of-use, in the case of ground tanks and community tankers. The latter could be attributed to unsanitary environments, poor hygiene practices or poor wateruse behaviour. Households which included children aged 0-5 years and in which open-top containers were used for water storage had the highest rates of diarrhoea and vomiting. Water from ground tanks had the best microbial quality but people in households using this water presented with the highest rate of diarrhoea. Therefore provision of microbially safe drinking water will not reduce the rate of health outcomes if addressed in isolation. In order to reduce water-associated illness, provision of safe and adequate amounts of water, hygiene and sanitation education and education on water-use behaviour should be provided as a package. The provision of improved water delivery systems does not ensure that drinking water is safe for human consumption. Measures, such as point-of-use water treatment should be considered to ensure that drinking water provided at the source and point-of-use is microbially safe for human consumption.
Thesis (M.Sc.)-University of KwaZulu-Natal, 2009.

Following the Second World War, the Food and Agriculture Organization (FAO) and the World Health Organization (WHO) teamed up to construct an international Codex Alimentarius (or “food code”) in 1962. Inspired by the work of its European predecessor, the Codex Europaeus, these two UN agencies assembled teams of health professionals, government civil servants, medical and scientific experts to draft food standards. Once ratified, the standards were distributed to governments for voluntary adoption and implementation. By the mid-1990s, the World Trade Organization (WTO) identified the Codex as a key reference point for scientific food standards. The role of science within this highly political and economic organization poses interesting questions about the process of knowledge production and the scientific expertise underpinning the food standards. Standards were constructed and contested according to the Codex twin goals of: (1) protecting public health, and (2) facilitating trade. One recent criticism of Codex is that these two aims are opposed, or that one is given primacy over the other, which results in protectionism. Bearing these themes in mind, in this dissertation I examine the relationship between the scientific and the ‘social’ elements embodied by the Codex food standards since its inception after the Second World War. I argue that these attempts to reach scientific standards represent an example of coproduction– one in which the natural and social orders are produced alongside each other. What follows from this central claim is an attempt to characterize the pre-WTO years of the Codex through a case study approach. The narrative begins with a description of the predecessor regional group the Codex europaeus, and then proceeds to key areas affecting human health: 1) food additives, 2) food hygiene, and 3) pesticides residues.