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Made available in DSpace on 2014-06-11T19:29:31Z (GMT). No. of bitstreams: 0 Previous issue date: 2006-11-13Bitstream added on 2014-06-13T19:59:10Z : No. of bitstreams: 1 mamprimfilho_a_me_botfmvz.pdf: 296194 bytes, checksum: 44831a4a7dcb550b37a439f99cb38280 (MD5) / Os manipuladores são importantes peças na qualidade dos alimentos, podendo ser causadores de intoxicações de origem alimentar, pela introdução de patógenos nos alimentos durante o processamento, distribuição e manipulação. As fossas nasais têm sido relatadas como a fonte mais importante de disseminação de Staphylococcus enterotoxigênico, seguido pelas mãos dos manipuladores. Nesse trabalho pesquisou-se a presença de estafilococos coagulase negativa e positiva em 3 cozinhas industriais diferentes entre 82 manipuladores de alimentos, onde foram analisados os esfregaços de fossas nasais e das mãos, com isolamento e identificação de 62 cepas coagulase-negativa (75,6%) e 20 cepas coagulase-positiva (24,4%). A prevalência dos isolados foi de 20 (24,4%) para S. aureus, 37 (45,1%) para S. warneri, 23 (28%) para S. epidermidis e 1 (1,2%) para as espécies S. capitis e S. xylosus.Os genes das enterotoxinas estafilocócicas A, B, C, D, E, G, H, I e J foram pesquisados pela PCR e entre as 20 cepas de Staphylococcus coagulase positiva, 19 (95%) foram positivas para um ou mais genes que codificam para as diversas enterotoxinas pesquisadas. O número de ECN produtores de enterotoxinas foi alto, de 46,8% (29 cepas positivas). Considerando-se todas as enterotoxinas, independente da espécie de Staphylococcus, o tipo mais comum foi a do tipo A, sendo observada em 17 cepas (35,4%) desse gênero, seguida por SEH e SEJ, ambas com 14 isolados (29,2%), SEG, sendo produzida por 13 cepas (27,1%), SEI, por 11 (22,9%) e SEE, SEB e SEC, por 7 (14,6%), 6 (12,5%) e 5 (10,4%), respectivamente. A SED não foi observada. A pesquisa das novas SES aumentou consideravelmente a porcentagem de cepas exterotoxigênicas dos dois grupos, aumentando assim, o potencial patogênico desse grupo de bactérias O papel dos ECN deve ser revisto e sua importância, reconhecida, pois, sempre foram considerados contaminantes de alimentos, sem despertar a atenção. / The food handlers are important parts in the quality of foods, being able to cause foodborne disease, by the introduction of pathogens during the processing, distribution and manipulation of foods. Nasal cavities are the most important source of dissemination of enterotoxigenic Staphylococcus, followed by hands. The aim of this study was search negative and positive coagulase Staphylococcus in 82 food handlers distributed among three different industrial kitchens, analyzing nasal and hands swabs, with isolation and identification of 62 coagulase-negative (75,6%) and 20 coagulase-positive strains (24,4%). The prevalence was of 20 isolated (24,4%) for S. aureus, 37 (45,1%) for S. warneri, 23 (28%) for S. epidermidis and 1 (1,2%) for S. xylosus and S. capitis. Staphylococcal enterotoxins genes (A, B, C, D, E, G, H, I e J) had been searched by PCR. In 20 positive coagulase Staphylococcus, 19 (95%) were positive for one or more genes. The number enterotoxigenic ECN was high (46,8%). Considering all enterotoxins, independent of the species of Staphylococcus, the more common was SEA (35,4%), followed for SEH and SEJ, both with 14 strains (29,2%), SEG, being produced by 13 isolates (27,1%), SEI (22,9%) and SEE, SEB and SEC, for 7 (14,6%), 6 (12,5%) and 5 strains (10,4%), respectively. The SED was not observed. The detection of new SES increased the number of enterotoxigenic isolates in both groups, with the growing of pathogenic potential in this genus. The paper of ECN should be reviewed and its importance, recognized, because, had been always considered as contaminants of foods, without pay attention.

O objetivo foi avaliar a ação do ácido indol-3-acético (AIA) na ausência e presença da peroxidase de raiz forte (HRP) sobre a viabilidade de cepas certificadas de Staphylococcus aureus ATCC 6538 (produtora de biofilme), ATCC 14458 (portadora do gene seb), ATCC 43300 (portadora do gene mecA) e ATCC 29213 (controle). Foi determinada a concentração inibitória mínima (CIM) e, após, escolheu-se uma concentração subinitória para avaliar a capacidade de formação de biofilme, atividade de enzimas antioxidantes, integridade de DNA, integridade de membrana para todas as cepas e avaliação da expressão do gene seb da cepa ATCC 14458. A CIM observada foi de 40 mM de AIA para cepa ATCC 6538, 60 mM para ATCC 43300,50 mM para ATCC 14458 e ATCC 29213. No entanto, houve diferença significativa (P<0,05), na presença de HRP, somente para as cepas ATCC 14458 e 43300. A concentração subinibitória de AIA utilizada foi de 30 mM para ATCC 6538 e ATCC 14458, e de 40 mM para ATCC 43300 e ATCC 29213.mM. A capacidade de formação de biofilme pelo S. aureus(biofilme positivo) não foi alterada pela presença de AIA ou AIA/HRP. A atividade específica de catalase e superóxido dismutase foi aumentada pela ação de AIA/HRP (P<0,05) para todas as cepas, porém, não houve diferença (P>0,05) entre AIA e AIA/HRP. O DNA manteve-se íntegro, porém, houve diminuição na integridade de membrana (P<0,05) para todas as cepas cultivadas na concentração subinibitória de AIA, sendo este efeito potencializado na presença de HRP somente para ATCC 43300. Houve redução na expressão do gene seb da cepa ATCC 14458 (P<0,05). Conclui-se que o AIA, associado à HRP apresenta efeito bacteriostático em cepas de Staphylococcus aureus portadoras de diferentes fatores de virulência. / The objective was to evaluate the action of indole-3-acetic acid (IAA) in the absence and presence of horseradish peroxidase (HRP) on the viability of certified strains of Staphylococcus aureus ATCC 6538 (producer of biofilm), ATCC 14458 (carrying the seb gene), ATCC 43300 (carrying the mecA gene) and ATCC29213 (control). Concentration was determined minimum inhibitory (CIM) and, after, we chose a concentration subinitória to assess the ability of biofilm formation, activity of antioxidant enzymes, integrity DNA, membrane integrity for all strains and evaluation of gene expression seb of strain ATCC 14458. The MIC for the strains ATCC 6538 was 40 mM IAA , for the strains ATCC 14458 and 29213 was 50 mM and for the strain ATCC 43300 was 60 mM IAA, however, significant differences (P<0.05) compared to the addition of HRP to the culture medium, was found only for the doses of MIC of the strains ATCC14458 and 43300. The concentration subinibitória IAA used was 30 mM for ATCC 6538 and ATCC 14458, and 40 mM to ATCC 43300 and ATCC 29213.mM for ATCC 6538 and ATCC 14458, and 50 mM to ATCC 43300 and ATCC 29213.The ability of biofilm formation by S. aureus(biofilm-positive) was not altered by the presence of IAA or IAA/HRP in the culture medium. The activity of catalase and superoxide dismutase was influenced by the action of IAA and IAA/HRP (P<0.05), but there was no difference (P≥0.05) between IAA and IAA/HRP. The DNA remained intact, however, there were changes (P<0.05) in the membrane integrity of microorganisms to sub-inhibitory concentrations of IAA and IAA/HRP, as well as the expression of the sebgene was lower (P<0.05) in microorganisms treated with IAA and IAA/HRP. It is concluded that the IAA has bacteriostatic effect on S. aureus carrying different virulence factors.

Orientador: José Luiz Pereira / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia de Alimentos / Made available in DSpace on 2018-08-21T19:43:45Z (GMT). No. of bitstreams: 1 Amaro_EmersonClayton_M.pdf: 844118 bytes, checksum: b0bffa4676cd77fbb9f0b90845077d5d (MD5) Previous issue date: 2013 / Resumo: Várias doenças são transmitidas por alimentos e existem grupos de indivíduos mais vulneráveis,em especial as crianças, sendo desta forma prioridade nas ações de atenção à saúde. Segundo a Organização Mundial da Saúde (OMS), ocorrem mais de 1,8 milhões de mortes de crianças com menos de cinco anos de idade devido ao consumo de alimentos contaminados. Os agentes etiológicos mais frequentes em surtos no Brasil são a Salmonella spp, Staphylococcus aureus, Escherichia coli, Bacillus cereus e Clostridium perfringens. Desta forma essa pesquisa teve o intuito de avaliar se os alimentos prontos para consumo servidos nas creches em Campinas (SP) cumprem os requisitos exigidos pela legislação. A pesquisa foi realizada em quatro creches na cidade de Campinas/SP (em diferentes regionais), escolhidas por sorteio com o auxílio da Coordenadoria de Vigilância em Saúde de Campinas. Foram analisados alimentos prontos para o consumo servidos para crianças de 1 a 4 anos, sendo a refeição escolhida o almoço, também foram analisados superfícies, utensílios e mãos de manipuladores. Quanto a contagem de coliformes termotolerantes, Staphylococcus coagulase positiva e contagem de aeróbios mesofilos, essas amostras foram coletados com auxilio de swab estéreis. As análises nos alimentos constataram que 97% dos alimentos estão dentro dos limites estabelecidos, 6,6% das amostras apresentaram presença de coliformes termotolerantes, sendo que 3,3% das amostras apresentaram presença de E.coli. A pesquisa de Staphylococcus coagulage positiva nos alimentos indicaram que 3,3% das amostras continham esse tipo de micro-organismo, mas em baixa contagem, estando dentro do permitido pela legislação. As analises de superfícies, utensílios e mãos de manipuladores apresentaram contagem de coliformes termotolerantes <3 NMP/g, para contagens de Staphylococcus coagulase positiva, 61% da amostras apresentaram presença destes microorganismos e para contagens de aeróbio mesófilos, 100% das amostras apresentaram valores superiores aos estabelecidos pela Associação Americana de Saúde Publica (APHA). Com os resultados apresentados no presente estudo, fica evidente a necessidade de melhorar as condições higiênico-sanitárias do ambiente de preparo dos alimentos e dos manipuladores dos alimentos / Abstract: Several diseases are transmitted by food and there are groups of individuals that are more vulnerable than others, especially children, thereby being priority actions in health care. According to the World Health Organization (WHO), there are more than 1.8 million deaths of children under the age of five due to consumption of contaminated food. The most common etiologic agents in outbreaks in Brazil are Salmonella spp, Staphylococcus aureus, Escherichia coli, Bacillus cereus and Clostridium perfringens. Therefore this study aimed to assess whether the ready to eat foods served in child care centers in Campinas (SP) meet the requirements mandated by the legislation. The research was conducted in four kindergartens in the city of Campinas / SP (in different regional), chosen at random with the assistance of the Coordinator for Health Surveillance of Campinas. We analyzed food ready for consumption served to children aged 1 to 4, for lunch. Analyses of surfaces, utensils and hands of the manipulators, as well as the counting of thermo tolerant coliforms, coagulase positive Staphylococcus and mesophilic aerobic were also carried out. These samples were collected with the aid of sterile swabs. Our results showed that 97% of analyzed food are within established limits, 6.6% of the samples showed the presence of fecal coliform, and 3.3% of the samples showed the presence of E.coli. As for coagulase positive Staphylococcus, 3.3% of the samples contained this type of micro-organism,but in low count, being within the permitted limits. The analysis of surfaces, utensils and hands of the handlers showed fecal coliform <3 MPN / g, 61% of the samples showed the presence of coagulase positive Staphylococcus and for mesophilic aerobic 100% of the samples had higher numbers than those established by the American Association of Public Health (APHA). With the results presented in this study, the need to improve the hygienic-sanitary conditions of the environment of food preparation and also of the food handlers is evident / Mestrado / Ciência de Alimentos / Mestre em Ciência de Alimentos

Submitted in fulfillment of the academic requirement for a degree in Doctor of Philosophy (Ph.D.) in Food Science and Technology, Durban University of Technology, Durban, South Africa, 2017. / There has been a global increase in fresh produce consumption, due to its attendant nutritional a nd health benefits. On the other hand, increase in the outbreak of diseases, accompanied with health and economic implications, have been traced to this deve lopment. A good number of pathogenic contaminants along the food chain have been identified as causative agent s with Listeria monocytogenes identified as one of such. Among other control strategies, the use of bacteriophage, was recommended as a palliative measure. Furthermore, the a ppli cation of artificial neural networks (ANN) in food safety remains an emerging concept in risk assessment study. Therefore, the aim of this research is to investigate the effect of bacteriophage or phage control and artificial neural network prediction in the inactivation of L. monocytogenes ATCC 7644 on fresh produce. Fresh-cut tomato and carrot were artificially inoculated with L. monocytogenes (108 CFU/ml) and subjected to antimicrobial treatment of Listex P100 bacteriophage (108 PFU/ml), sucrose monolaurate (SML at 100, 250 and 400 ppm), with chlorine (sodium hypochlorite at 200 ppm) used as control. Also, application of ANN to predict the risk effect of antimicrobial treatments of bacteriophage, sucrose monolaurate and chlorine was evaluated on the fresh-cut produce. Mathematical models were developed using a linear regression and sigmoid (hyperbolic and logistic) activation function-(120). Data sets were trained using Back propagation ANN, containing one hidden layer with four hidden neurons. Furthermore, carbon utilization profile of phage-treated L. monocytogenes using phenotypic micro array method was evaluated. In the first phase, susceptibility of L. monocytogenes subjected to certain stress-adapted conditions (acid,-adapted AA, chlorine-adapted CA, heat-adapted HA) and non-adapted-NA to phage treatment inoculated on the fresh-cut produce stored for 10 days at 4, 10 and 25oC was evaluated. The second phase investigated the combination of bacteriophage and sucrose monolaurate (using chlorine at 200 ppm as control) to inhibit the L. monocytogenes growth on the fresh-cut produce stored for 6 days at 4, 10 and 25oC. Physicochemical properties (pH, titratable acid-TTA, total soluble solids-TSS, and colour values-CIE L* a* b*) of the fresh produce after treatment were evaluated. In the third phase, ANN as a predictive tool was used to evaluate the risk involved in the relationship among the initial bacterial load, fresh-produce type, antimicrobial concentration and residual bacteria. In the final phase, 100 µL of phage-treated L. monocytogenes was introduced into a 96-micro well plate impregnated with a tetrazolium dye. The Carbon utilization profile was evaluated at intervals of 4 hours for 48 hours using a biolog micro station. Generally, L. monocytogenes grew on both fresh-cut produce and the storage temperature did not adversely affect the lytic ability of the phage treatment. Antimicrobial treatment of phage and sucrose monolaurate had minimal variations on the physicochemical properties of both fresh-cut samples. All stress-adapted and non-adapted L. monocytogenes were (p ≤ 0.05) susceptible to bacteriophage control. Phage treatment reduced non-adapted, acid adapted, chlorine-adapted, and heat-adapted L. monocytogenes population by 0.57, 0.81, 0.86 and 0.95 log CFU/ml in fresh-cut tomato, and 2.26, 2.41, 2.49 and 2.54 log CFU/ml in fresh cut carrot respectively. Furthermore, the additive effect of SML at 100 and 250 ppm had no significant effect on phage lysis. However, combination of phage with SML at 400 ppm significantly (p ≤ 0.05) resulted in 1 and 3 fold reductions in tomato and carrot respectively. Control treatment with chlorine resulted in 1-2 log reductions on both fresh produce. Algorithm data set trained using ANN gave 100% accuracy. Prediction with logistic activation function showed the highest positive correlation relationship between predicted and observed values with ~ 0.99 R2-value and MSE of 0.0831. Carbon utilization profile showed hexose and pentose sugars-ribose, glucose, fructose and sugars were maximally utilized while oligosaccharide sugars of sucrose, cellobiose and gentiobiose were similarly observed to be utilized. Notably, utilization of glucose-6-phosphate which determines L. monocytogenes pathogenicity was not very pronounced in the carbon profile. Bacteriophage application in the inactivation of L. monocytogenes contamination of fresh produce provides a safe means of control. Its perceived limitation however, can be overcome by combining with other antimicrobials. Similarly, the use of artificial neural networks prediction, remains an improved approach to harness the potential risk that could occur through this method. / D

Magister Public Health - MPH / This study is aimed to assess the extent of street food vendor information and education on food safety. Aim: To determine the knowledge, attitudes and practices (KAP) of street food vendors, within the City of Johannesburg, with regard to food hygiene and safety. Methods: A descriptive, cross-sectional study utilizing a quantitative research approach. Data was collected through face-to-face interviewing of street food vendors, with observations of general hygiene and cleanliness. Data was captured in Excel and imported into CDC Epi Info version 3.4.3 (2007) for analysis. Numerical data was analyzed using descriptive statistics and categorical data was analyzed using frequencies. Bivariate analysis was used to establish differences between regions with high and low proportions of street food vendors with regard to knowledge, practices and attitudes variables. / South Africa

Clostridium perfringens is a significant human pathogen, causing 250,000 cases of food poisoning in addition to several thousand potentially lethal cases of gas gangrene each year in the United States. Historically, work in this field has centered around toxin production, as C. perfringens can produce over 13 toxins. This work expands the knowledge of the starvation-response of C. perfringens, which includes several potential virulence factors, sporulation, motility and biofilm formation. Sporulation protects cells from a variety of stresses, including starvation. Efficient sporulation requires the transcriptional regulator CcpA, mediator of catabolite repression. Sporulation is repressed by glucose, but, surprisingly, in a CcpA-independent fashion. C. perfringens cells in a biofilm are resistant to a number of environmental stresses, including oxygen and antibiotics. Biofilm formation is repressed by glucose, and other carbohydrates, independently of CcpA. Gliding motility, a type four pili (TFP)-dependent phenomenon, affords C. perfringens with a mechanism for moving across a solid surface in response to carbohydrate starvation, while carbohydrates supplementation at high levels delay the initiation of the motility response. CcpA is required for the proper initiation of motility, a ccpA^-C. perfringens strain showed a considerable increase in the time to initiation of motility on lactose and galactose, and was unable to move at all in the presence of glucose. Gliding motility represents the most significant finding of this work. TFP were previously undescribed in any Gram-positive bacterial species, and this work produced genetic evidence suggesting their presence in all members of the clostridia, and physical evidence for TFP-dependent gliding motility in a second species, C. beijerinckii. / Ph. D.

The purposes of this study are, first, to determine relative numbers and predominant types of bacterial organisms in the various food products studied; second, to evaluate the efficiency of the paper coverings of these foods; and third, to determine whether these products are potential sources of food poisoning.

This study is aimed to assess the extent of street food vendor information and education on food safety. Aim: To determine the knowledge, attitudes and practices (KAP) of street food vendors, within the City of Johannesburg, with regard to food hygiene and safety. Methods: A descriptive, cross-sectional study utilizing a quantitative research approach. Data was collected through face-to-face interviewing of street food vendors, with observations of general hygiene and cleanliness. Data was captured in Excel and imported into CDC Epi Info version 3.4.3 (2007) for analysis. Numerical data was analyzed using descriptive statistics and categorical data was analyzed using frequencies. Bivariate analysis was used to establish differences between regions with high and low proportions of street food vendors with regard to knowledge, practices and attitudes variables.

This study is aimed to assess the extent of street food vendor information and education on food safety. Aim: To determine the knowledge, attitudes and practices (KAP) of street food vendors, within the City of Johannesburg, with regard to food hygiene and safety. Methods: A descriptive, cross-sectional study utilizing a quantitative research approach. Data was collected through face-to-face interviewing of street food vendors, with observations of general hygiene and cleanliness. Data was captured in Excel and imported into CDC Epi Info version 3.4.3 (2007) for analysis. Numerical data was analyzed using descriptive statistics and categorical data was analyzed using frequencies. Bivariate analysis was used to establish differences between regions with high and low proportions of street food vendors with regard to knowledge, practices and attitudes variables.