Inledning: Salladsbarer är ett trendigt och lättillgängligt måltidsalternativ som finns i de flesta dagligvaruhandelsbutiker. Personal och konsumenter hanterar dagligen livsmedel och utrustning vid salladsbaren. Det saknas idag information och kunskap om hur personers beteende kring en salladsbar kan påverka livsmedelssäkerheten. Syfte: Undersöka risker med offentlig livsmedelshantering vid en salladsbar. Metod: Dolda observationer av personal och konsumenters riskbeteende. Hygienkontroll av portionsförpackningar. Bakterieprovtagningar av ytor i anknytning till salladsbaren följt av en artbestämning. Studiens intention är att ge en kvalitativ bild av de hygienutmaningar som livsmedelshantering i en offentlig miljö kan innebära. Resultat/Slutsats: Resultatet av observationerna visar att det sker ett flertal olika riskbeteende i anknytning till salladsbaren, framför allt bland konsumenter, vilket kan leda till korskontamination. Hygienkontrollen visade att medelvärdet av samtliga portionsförpackningar låg inom gränsvärdet för godkänd hygienstandard. Analysen av bakterieprover tagna från olika ytor kopplade till salladsbaren visade att det förekommer en hög variation av olika bakterier. Det finns en risk för bakteriespridning genom personers riskbeteende kopplade till salladsbaren. Risker kan förebyggas genom ökad kunskap och information om hygien och normer för beteende kring salladsbarer. / Introduction: Salad bars are a trendy and easily accessible meal option available in most grocery stores. Staff and consumers handle food and equipment at the salad bar daily. There is today no information and knowledge about how people's behavior around a salad bar can affect food safety. Purpose: To investigate risks with public food management at a salad bar. Method: Hidden observations of staff and consumer risk behavior. Hygiene control of portion packages. Bacterial sampling of surfaces associated with the salad bar followed by a species determination. The aim of the study is to provide a qualitative picture of the hygiene challenges that food management in a public environment may imply. Result/Conclusion: The results of the observations show that there are a variety of risk behaviors associated with the salad bar, especially among consumers, which can lead to cross contamination. The hygiene check showed that the average of all portion packages was within the limit of approved hygiene standards. The analysis of bacterial samples taken from different surfaces linked to the salad bar showed that there was a high variety of different bacteria. There is a risk of bacterial spread through people's risk behavior linked to the salad bar. Risks can be prevented through increased knowledge and information on hygiene and norms around salad bars.

Orientadores: Luiz Augusto Corrêa Passos, Ana Maria Aparecida Guaraldo / Tese (doutorado) - Universidade Estadual de Campinas, Instituto de Biologia / Made available in DSpace on 2018-08-26T12:27:38Z (GMT). No. of bitstreams: 1 LabelloBarbosa_Rodrigo_D.pdf: 3872986 bytes, checksum: eed1c71b567c33f273e37132ebefabcc (MD5) Previous issue date: 2014 / Resumo: Na amazônia brasileira, microepidemias de doença de Chagas aguda (DCA) humana são notificadas por meio de caracterização clínica e epidemiológica após associação ao consumo de polpa in natura de açaí contaminada com Trypanosoma cruzi. Dada a sua relevância econômica, cultural e considerando que a refrigeração e o congelamento não são métodos eficientes à prevenção da DCA de transmissão alimentar, os objetivos desse estudo foram determinar um binômio "temperatura x tempo" mínimo necessário à inativação ou morte do T. cruzi em polpa de açaí e avaliar a possibilidade experimental da transmissão dessa parasitose, proveniente de vetores e reservatório de diferentes localizações do Estado do Pará, por contaminação acidental no alimento. Na primeira etapa, 105 tripomastigotas da cepa Y de T. cruzi foram misturadas à polpa in natura de açaí e submetidas a tratamentos térmicos entre 37ºC e 49ºC em um banho ultratermostático de alta precisão, por até uma hora, sob homogeneização constante. Na segunda etapa, 105 tripomastigotas de T. cruzi (TcI) de diferentes fontes e localizações do Pará, comparando-se à cepa Y de T. cruzi (TcII), foram misturadas, à temperatura ambiente, à polpa in natura de açaí. Em ambas etapas, quando necessário, as misturas contaminadas foram submetidas à tamisação forçada. O inóculo (controle negativo, controle positivo ou grupo teste), de até 200?L, foi administrado via intraperitoneal, gavagem ou oral em hospedeiros isogênicos imunodeficientes C.B-17-Prkdcscid/Pas Unib ou B6.129S7Rag1-/-tmMom/J Unib, sob antibioticoterapia prévia (1,75mg/dia). A parasitemia foi realizada de acordo com o método de Brener e a mortalidade foi registrada. T. cruzi preservou sua virulência em polpa de açaí à 43±0,1ºC durante 20 minutos, causou DCA e morte em até 24 dias após as infecções experimentais, via intraperitoneal. T. cruzi de R. pictipes da Mata do Val-De-Cans, de Belém, apresentou DCA, com início de parasitemia e morte, respectivamente, nos dias 32,0±3,0 e 40,0±3,0. T. cruzi de R. pictipes do Rio Ajuaí, de Abaetetuba, apresentou DCA, com início de parasitemia e morte, respectivamente, nos dias 35,0±1,0 e 49,0±1,0. T. cruzi de P. opossum da Ilha do Combu, de Belém, apresentou DCA, com início de parasitemia e morte, respectivamente, nos dias 45,0±2,0 e 51,0±1,0, via oral. Não houve diferença significativa para a DCA de vetores de diferentes localizações, contudo, houve diferença significativa para a DCA entre T. cruzi de vetores e reservatório, bem como em relação à cepa Y de T. cruzi (teste de Duncan, 99% de confiança). Portanto, a cocção da polpa in natura de açaí acima de 44ºC poderá prevenir a DCA de transmissão alimentar. T. cruzi obtidos de diferentes fontes e localizações do Pará, após o contato com a polpa in natura de açaí, à temperatura ambiente, foram capazes de preservar sua virulência in vivo, causar DCA e morte em até 52 dias após as infecções experimentais. Uma educação básica de qualidade facilitará que boas práticas de higiene ocorram durante toda a cadeia produtiva do açaí e evitará a ocorrência de DCA de transmissão alimentar na região Norte do país nas próximas décadas / Abstract: In the Brazilian Amazon, outbreaks of acute Chagas¿ disease (ACD) in humans are reported by clinical and epidemiological characterization after association with the ingestion of in natura fruit¿s açai of pulp contaminated with T. cruzi. Due the economic and cultural relevance and considering that the cooling and freezing are not efficient to prevent the ACD foodborne, the aims of this study were determine a minimum binomial "temperature x time" and necessary to inactivation or death of T. cruzi in fruit¿s açai of pulp and evaluate the possibility of experimental transmission of this parasitosis, from vectors and reservoir at different locations at Pará State, in an accidental contamination in food. In the first stage, 105 trypomastigotes of T. cruzi Y strain were mixed with in natura fruit¿s açai of pulp and heat-treated between 37ºC and 49ºC in a high-precision water bath, by up to an hour, under constant homogenization. In the second stage, 105 trypomastigotes of T. cruzi (TcI) from different sources and locations at Pará, comparing with T. cruzi Y strain (TcII), were mixed with in natura fruit¿s açai of pulp, at room temperature. In both stages, when necessary, contaminated mixtures were subjected to forced sieving process. The inoculum (negative control, positive control or test group), up to 200 ?L, was administered intraperitoneal, gavage or oral in inbred immunodeficient hosts CB-17-Prkdcscid/Pas Unib or B6.129S7Rag1-/-tmMom/J Unib, under previous antibiotic therapy (1,75 mg/day). Parasitemia was scored as recommended by Brener and mortality registered. T. cruzi retained its virulence in fruit¿s açai of pulp at 43±0,1ºC for 20 minutes, caused ACD and death in mice up to 24 days after experimental infections, intraperitoneally. T. cruzi from Rhodnius pictipes, Val-de-Cans¿ forest, Belém, presented ACD and death, respectively, on days 32,0±3,0 and 40,0±3,0. T. cruzi from R. pictipes, Ajuaí River, Abaetetuba, presented ACD and death, respectively, on days 35,0±1,0 and 49,0±1,0. T. cruzi from Philander opossum, Combu¿s Island, Belém, presented ACD and death, respectively, on days 45,0±2,0 and 51,0±1,0, orally. There was not significant difference for the ACD from vectors of different locations, however, there was significant difference for the ACD between T. cruzi from vectors and reservoir, as well as for the T. cruzi Y strain (Duncan test, ? 0,01). Therefore, cooking in natura fruit¿s açai of pulp above 44ºC can prevent ACD foodborne. T. cruzi from different sources and locations at Pará, after contact with in natura fruit¿s açai of pulp, at room temperature, can retain its virulence in vivo, cause ACD and death in up to 52 days after experimental infections. A quality basic education will facilitate good hygiene practices occur throughout the productive chain of açai and will prevent ACD foodborne in the northern region of Brazil in next decades / Doutorado / Parasitologia / Doutor em Parasitologia

Human noroviruses are a major cause of acute gastroenteritis worldwide and can betransmitted through consumption of contaminated raw food. Shellfish like oysters can becontaminated by human sewage during production and accumulate multiple Norovirus strainsin low concentrations. Here we developed a simplified and cost effective targetedmetagenomic approach by sequencing PCR amplicons with next generation sequencing(NGS) of the capsid (VP1) viral gene. New design of reverse primers using the codehopstrategy and direct addition of illumina adapter with one step RT-PCR and sequencing onnano chip reduced hand on time and cost of the analysis. A mix of faecal samples and oystersamples associated with outbreaks were used to evaluate the ability and limitations in theidentification of strains from Norovirus genogroup I (GI) and genogroup II (GII). Withsamples containing only one genotype the method was able to identify all strains. Usingartificially mixed samples the method was able to identify almost all strains except a few GIIat low concentrations. Oyster samples showed more limitations for the method and it waswere only able to identify the strain in some of the samples but did find multiple GI strains inmore than one sample. Despite some limitations, the simplified method for VP1-targetedmetagenomics is a sensitive approach allowing the study of norovirus diversity incontaminated oysters and the identification of norovirus strains implicated in outbreaks. Thisat a lower cost and hands on time compared to published methods.

No description available.

No description available.

Thesis (D. Tech. (Biomed. Tech.)) -- Central University of Technology free State, 2010 / Consumer demands for fresh, microbiologically safe foods with high organoleptical and nutritional quality has led to the development of novel food preservation technologies as alternatives or enhancements to traditional preservation techniques. An example of these novel preservation technologies is high hydrostatic pressure (HHP) processing. It involves the applications of static pressure of 50 to 1 000 mega Pascals (MPa) to solid or packaged liquid foods, with varying holding times. The combination of factors to enhance preservation is increasingly being used in industry, e.g. the use of different temperatures and additives (hurdles) can enhance the preservative effect of HHP. In this study the influence of HHP on organism viability and growth response was assessed. The organisms evaluated included Escherichia coli O111, Listeria monocytogenes (UAFSBCC) and Staphylococcus aureus (ATCC 25923), in peptone water, which was subjected to HHP of 200 MPa for 15 minutes at 8 and 50 ºC respectively. Subsequent to the mentioned pressurisation, sub-culturing was performed and growth responses were evaluated at 0, 6, 18, 24, 30, 42 and 48 hours. Bacterial survival and growth response was measured by means of intact cell count, colony forming units and optical density. From the results it was eminent that bacterial cells were only sublethally injured and were able to repair within 48 hours of enriched sub-culturing. E. coli O111 proved to be most sensitive to HHP with Staphylococcus aureus (ATCC 25923) most resistant. This study also proved that bacterial concentration and inactivation rate are inversely proportionate to each other. Subsequent to growth and cell repair assessments, E. coli O111 was selected as a model to evaluate the effect of sublethal HHP on the liberation and toxicity of bacterial endotoxins (free and cell wall bound). It is also known that different extraction procedures extract different lipopolysaccharides (LPS) fractions and therefore LPS was extracted from the test broth by a combination method of Folch, Lees & Sloane-Stanley, and Venter and Ivanov. The extraction yielded a biphasic system, LPS with reduced lipid content in the upper phase (aqueous) and LPS with increased lipid content in the lower phase (organic). Following extraction the Limulus amebocyte lysate (LAL) test was performed to quantify the concentration (assumed) of LPS in the aqueous and organic phases. Free LPS was detected within six hours in the supernatant in the high and low bacterial loads, moreover the toxicity response of post HHP cell damage was more pronounced at 50 ºC (hurdle) than that observed for the treatments at 8 ºC (hurdle) and more so in the organic phases. The latter implied that HHP not only resulted in quantity LPS variation but also in structural change. However membrane repair was apparently complete after 48 hours, as differences in toxicity were no longer evident. Furthermore, the use of a porcine IL-6 ELISA assay was evaluated as an alternative for the customary LAL as a biomarker for pyrogenic substances in matrixes. Porcine whole blood was challenged for IL-6 production by LPS in the samples from the organic and aqueous systems. A porcine IL-6 enzyme-linked immunosorbent assay was used to assess IL-6 expression in whole blood after being challenged with LPS. From the results it emanated that HHP caused in a change in LPS structure which resulted in a decreased IL-6 expression in whole blood, indicating that structural adaptation of the cell membrane in response to HHP influenced the ability of LPS to stimulate macrophages and monocytes. Therefore, further research and development would be required to evaluate the influence of post HHP LPS on human IL-6 expression. When comparing the porcine IL-6 with the LAL no correlation in toxicity could be established in any of the treatment parameters. Finally it can be concluded that HHP had an influence in the structural morphology of LPS. These structural changes could result in LPS being more toxic, it could also have an effect on the accuracy of immunological assessments, the ability to form biofilm, and susceptibility to phages.

Thesis (M. Tech. Environmental health) -- Central University of technology, Free State, 2011 / Microbial pathogens play an important role in the food industry where they could cause disease and subsequently significant economic losses. Limited information is available on the situation with regard to Listeria in food products in South Africa. However, much research is being done in the rest of the world on Listeria indicating serious problems as a result of resistance development against various antimicrobial agents, including the organic acids. It is hypothesised that the situation with regard to resistance development may be more serious than generally admitted. Isolation of 200 different food samples was done by using a slightly modified EN ISO 11290-1/A1:2004 standard method. Identification of presumptive positive colonies was confirmed as Listeria by API (Analytical profile index) Listeria. API positive cultures were subjected to 16S rDNA sequencing to compare and confirm identification. Isolates and standard strains were screened for resistance to food preservatives such as organic acids and antibiotics used in the current treatment regime for Listeria infections. The organisms evaluated included isolated strains namely Listeria monocytogenes, Listeria welshimeri, Listeria innocua and their corresponding ATCC (American type culture colletion) strains. An agar dilution method as described by the Clinical and Laboratory Standard Institute (CLSI) was used to determine the minimum inhibitory concentrations (MICs) of 11 antibiotics and 13 organic acids and salts for all the isolates. Overall antibiotic susceptibility patterns of all the isolates indicated high level susceptibility to all the antibiotics tested. Susceptibility to all the organic acids was notably reduced at pH 7 in all the isolates and control strains. Eight highly susceptible strains were selected for induction and represented each of the species isolated. These isolates were exposed to increasing concentrations of three antibiotics and three organic acids. MICs were again determined for all the induced strains for five antibiotics and three organic acids. Proteins extracted from the induced strains were separated on discontinuous SDS-PAGE slab gels to generate total protein profiles. Notable variations were observed in MICs, although induction with antibiotics as well as organic acids did not result in general resistance development. However, evidence was provided that continuous exposure to antimicrobial agents may cause Listeria spp. to develop resistance to different antimicrobial agents. Further research and in depth studies on mechanisms involved in the development of resistance to food preservatives would, therefore, be required. Finally, it is concluded that Listeria monocytogenes may be a possible threat in the Central South African food industry, which deserves more attention. The situation may actually pose a problem that is overseen, because only a small percentage of people that get sick from food, would seek medical advice.

Thesis (M. Tech. Environmental health) -- Central University of technology, Free State, 2011 / The threat to the world food supply and the concern for public health as a result of food-borne diseases has been established as a constant global problem. The safety of food, in particular, is of significance to consumers and producers alike. Regarding the diseases related to food-borne pathogens, the disease syndromes affecting the entire human body has become inestimable. The focus of the study was to establish the effect of sanitisers, detergents and household storage temperatures on the growth profiles and toxicity of typical food related organisms. The endotoxin, LPS of these Gram-negative organisms in communal growth as compared to pure culture was the focus of the investigation. Pure and communal samples were grown in the presence of the extrinsic stresses including storage temperature. The change in toxicity was measured using the Limulus amoebocyte lysate test and the possible change in the immune response was determined using the porcine-IL-6 test. The first obvious finding was that the overall sensitivity of organisms was similar for the same sanitiser and the same detergent. The sensitivity of the community varied slightly but in principle followed the same pattern as the individual organisms. The LD50 for all growth samples were as follows: 32 X 104 PPM for sanitiser 1 and sanitiser 2, and 16X 104 PPM for detergent 1 and detergent 2. Growth in community was found not to be the arithmetic sum of the individual growth patterns. The detergents had a marked effect on the growth of all samples throughout the growth cycle. The sub-optimum household storage temperatures inhibited the growth throughout the cycle but growth did not cease entirely. This finding may have revealed that the acceptable refrigeration temperatures still allows for pathogen growth and thus for biofilm formation. Furthermore, the response of the community to the extrinsic stresses appears to be entirely different to the pure culture and therefore needs further exploration to address the problem. Regarding the quantification by LAL, it was found that the enumeration of the food-borne pathogens isolated from households might not be indicative of acclimatisation obtained over short periods of time and the causal stress turning these organisms into more or less toxic pathogens. The sanitisers and detergents induced competition in colonial fashion and the growth varied between feast and famine. The extrinsic stresses had a more observable effect on the older biofilm as this was shown by a decrease in toxicity. The toxicity as quantified by porcine-IL-6 yielded a mixture of stimulation levels for the cytokine. The toxicity change indicated by the test showed a variation between lowering and noticeable elevation for pure cultures. A marked elevation in toxicity was detected in community at storage temperature 4°C. The study would suggest that porcine IL-6 is not an accurate biomarker for pyrogenicity since its sensitivity is questionable and its inability to indicate toxicity if there is a possible change in the LPS structure. It should be said that further elucidation is needed to support this finding. Having said all that, it is no surprise that the validation for the two tests favours the LAL procedure. The large room for pre-test stimulation in pigs’ blood also tends to cast a shadow on the IL-6 findings. The findings of the study contribute to the body of knowledge covering the effects and quantitative analysis of toxins in food. This should add to safety assurance by sensitizing the industry regarding the most suitable analytical methodologies to apply.

Thesis (M. Tech. (Biomedical Technology)) -- Central University of technology, Free State, 2013 / The objective of this study was to determine the prevalence of Listeria monocytogenes and also to assess the general hygiene of fresh milk in the Maseru area, Lesotho. A total of 200 milk samples (40 pasteurised and 160 raw milk samples) were used for the research. Raw milk samples were collected from the local farmers at the Dairy reception as they bring it for selling. Pasteurised milk samples were bought from different milk selling points in the Maseru area. The total aerobic plate count, total coliform count and total E. coli count for 160 raw milk samples and 40 pasteurised samples were performed to determine the quality of milk. Milk was enriched in selective broths to increase detection sensitivity and was directly plated on selective agars for direct bacterial enumeration. About 54.4% of the of the raw milk samples had total aerobic plate counts greater that 200 000 cfu/ml while 55.6% (89/160) of the raw samples had high counts of greater than 20 cfu/ml for total coliforms, and 21.9% (35/160) of the samples had higher than expected total E. coli counts. High total coliform count was detected in 17.5% (7/40) of the pasteurised milk samples and about 67.5% (27/40) of these samples exceeded the limit for total aerobic plate counts. The counts exceeded the milk standards for pasteurised milk. Phosphatase activity was detected in seven pasteurised milk samples, whereas 33 tested negative for phosphatase activity. Some pasteurised milk samples tested positive for coliform counts which exceeded the maximum limits according to national standards for pasteurised milk. However, most of the pasteurised samples (82.5%) had acceptable counts of less than 20 cfu/ml. API and PCR were used for confirmation and amplification of the isolated Listeria strains. The prevalence of Listeria was found to be (3.75%). Listeria species were found in 6 out of 200 samples tested (160 raw milk samples and 40 pasteurised milk), and were only detected in the raw milk samples. Five species belonged to Listeria monocytogenes and one was Listeria innocua. None of the Listeria was detected in the pasteurised milk samples. Serotyping was done through multiplex PCR with D1, D2, FlaA and GLT primers to determine the serovar groups of L. monocytogenes. All six isolates revealed 214 bp gene which identifies the serotypes in Lineages I or III. The genetic fingerprinting of the isolated Listeria was also determined. Enterobacterial Repetitive Intergenic Consensus (ERIC) sequence-based PCR was used to generate DNA fingerprints with ERIC specific primers. On the basis of ERIC-PCR fingerprints, three different DNA patterns could be discriminated among the analysed isolates. Three L. monocytogenes isolates showed similar DNA banding patterns, while two isolates both had different profiles. A questionnaire was used to determine consumption of raw (unpasteurised) milk or pasteurised milk and its products and it was completed by 300 households from the community. Although there was no indicated prevalence of raw (unpasteurised) milk consumption from the community, participants indicated symptoms alleged to consumption of pasteurised milk and/or milk products. According to community perception some of the dairy products consumed were allegedly implicated in food poisoning illnesses experienced. Participants indicated more symptoms with both fresh and sour milk consumption than in cheese and yogurt consumption.

Master of Science / Department of Hospitality Management and Dietetics / Kevin R. Roberts / The Centers for Disease Control and Prevention estimated that one in six Americans become ill,128,000 are hospitalized, and 3,000 die each year due to foodborne illness. Children are at a higher risk of acquiring foodborne illness than adults for several reasons, including: an immune system that has yet to fully develop, limiting their ability to fight infections; a lack of control over the food they consume because their meals are usually provided by others; and the lack of awareness of food safety risks. Thus, it is critical to ensure that childcare center employees practice safe food handling. The purpose of this study was to explore the food safety knowledge, practices, and barriers to safe food handling practices of childcare center employees. Observations were conducted in 10 childcare centers in Manhattan, Kansas. Each childcare center was observed for two days during lunch preparation and service. Observations of foodservice employees were conducted in the kitchen using a structured observation form. Teacher observations were conducted in the classroom using detailed notes. A questionnaire was used to collect demographic, food safety training, and food safety knowledge information. SPSS (v. 20.0) was used to analyze data. Childcare center employees had high average scores on the safety knowledge assessment. The majority of employees received some type of food safety training. Time pressures, availability of equipment, and small food preparation space were found as the main barriers to implementing safe food handling. Childcare center foodservice workers and teachers were knowledgeable about handwashing and time/temperature control, but failed to utilize on the job. Results of this study will help childcare educators to develop materials to improve food safety practices and encourage owners/managers of childcare centers to enhance their food safety behaviors.