In recent years, due to the increasing number of produce-related outbreaks, greater attention has been given to interventions that remove human pathogens on fresh produce. Survival of Salmonella Poona on the surface and stem scar portions of inoculated cantaloupe, effect of chlorine or lactic acid or ozone on the survival of bacteria, transfer of pathogen from the rind to the fresh-cut tissue during cutting and growth and survival of Salmonella Poona on the fresh-cut tissues during 15 days of refrigerated storage were investigated. Preliminary studies were conducted to confirm that the rifampicin-resistant strain used in the study was indistinguishable from the parent strain of Salmonella Poona. Growth curve, heat tolerance and lactic acid resistance studies were performed, all of which showed no differences in behavior between the organisms. Cantaloupes were immersed in an inoculum containing rifampicicn-resistant strain of Salmonella Poona (107 CFU/ml) for 3 min and then dried for 12 h. The inoculated melons were washed with chlorine (200 ppm) for 3 min or lactic acid (2%) for 2 min or ozone (30 ppm) for 5 min and fresh cut tissues were prepared by peeling the rind and cutting into pieces or cutting the melon and removing the rind. Results obtained indicate that the levels of Salmonella Poona recovered were higher when the sample was obtained from the scar portion than the surface. Surface treatment with tap water or chlorine did not reduce Salmonella Poona. However treatment with lactic acid or ozone reduced the levels by 2.5 and 2.3 log10 CFU/cm2 respectively on the surface. Fresh-cut tissue prepared from melons sanitized with lactic acid resulted in less transfer during cutting and reached below detectable limits after 9 days of refrigerated storage. Cutting melons after peeling the rind was found effective in reducing the transfer of Salmonella Poona into the tissue in comparison with cutting of melons and removing the rind later. Thus these data suggest that treatment with lactic acid and ozone may be effective in reducing Salmonella from the surface of the cantaloupe where as lactic acid was effective in reducing the transfer from the surface to the flesh.

O objetivo do presente estudo foi avaliar a capacidade de isolados de Listeria monocytogenes em formar biofilmes em superfícies inertes, bem como sua resistência a agentes sanitizantes. Foram utilizados 37 isolados provenientes de ambiente de laticínios, amostras de queijos e salmoura, pertencentes à coleção do Laboratório de Microbiologia e Micotoxicologia de Alimentos (LMMA) do Departamento de Engenharia de Alimentos da FZEA/USP. Dos 37 isolados avaliados, 67,6% eram pertencentes ao sorotipo 4b. Três isolados de L. monocytogenes foram obtidos de salmoura, 5 foram obtidos de caixas plásticas, 1 de queijo Prato, 1 da mão de manipulador de embalagens, e 27 foram isolados de superfícies sem contato com alimentos (piso da sala de pasteurização, piso da câmara fria, ralo da câmara fria ou estrado da câmara fria). Os isolados de L. monocytogenes apresentaram maior capacidade de produzir biofilme nos ensaios com cupons de aço inox (43,2% dos isolados), seguido dos ensaios em microplaca de poliestireno (16,2%), cupons de borracha (13,5%) e discos de silicone (2,7%). As células de L. monocytogenes aderidas nas superfícies do aço inox foram visualizadas sob microscopia eletrônica de varredura após 48 horas de incubação a 37ºC. Dezenove isolados de L.monocytogenes, os quais produziram biofilmes nos ensaios com aço inox, borracha ou silicone, foram testados para determinação da eficiência de sanitizantes pelo método de concentração inibitória mínima (CIM), utilizando-se ácido peracético (2%), cloreto de banzalcônio (1%), digluconato de clorexidina (2%), hipoclorito de sódio (2%) e tintura de iodo (2%). Os isolados de L. monocytogenes analisados apresentaram resistência a ácido peracético, hipoclorito de sódio e tintura de iodo, cujos valores de CIM foram 3,12%, 6,25% e 6,25%, respectivamente. Nenhum isolado apresentou resistência a cloreto de benzalcônio e digluconato de clorexidina, os quais foram eficientes para inibição de isolados de L. monocytogenes provenientes de amostras de queijos e ambientes de laticínios. A L. monocytogenes apresenta capacidade de persistir em ambiente de laticínios sob a forma de biofilme em várias superfícies inertes como aço inox, borracha e silicone, o que pode representar uma fonte permanente de contaminação para produtos e processos de obtenção de leite e derivados. / The objective of the present study was to evaluate the ability of isolates of Listeria monocytogenes to form biofilms and their resistance to sanitizers. Thirty seven strains belonging to the collection of the Laboratory of Microbiology and Food Mycotoxicology (LMMA), Department of Food Engineering of FZEA / USP, were used. Of the 37 isolates, 67.6% belonged to serotype 4b. Three isolates of L. monocytogenes were obtained from brine, 5 were obtained from plastic boxes, one of Prato cheese, one from the packaging handler\'s hand, and 27 were isolated from non-food contact surfaces (pasteurization room floor, the floor of the cold room, the drain cold or pallet from the cold chamber). The isolates of L. monocytogenes showed greater ability to produce biofilm in the assays with stainless steel coupons (43.2% of isolates), followed by polystyrene micro plate (16.2%), rubber coupons (13.5%) and silicone disks (2.7%) assays. Cells of L. monocytogenes attached to stainless steel surfaces were viewed under scanning electron microscopy after 48 hours incubation at 37°C. Nineteen strains of L. monocytogenes, which were considered biofilms producers in the assays with stainless steel, rubber or silicone, have been tested to evaluate the efficiency of the sanitizing method by means of the minimum inhibitory concentration (MIC), using peracetic acid (2%), sodium chloride benzalkonium (1%), chlorhexidine digluconate (2%), sodium hypochlorite (2%) and iodine solution (2%). The isolates of L. monocytogenes analyzed showed resistance to peracetic acid, sodium hypochlorite and iodine tincture, with MIC values of 3.12%, 6.25% and 6.25%, respectively. No isolate showed resistance to benzalkonium chloride and chlorhexidine digluconate, which were effective for inhibiting the isolates of L. monocytogenes from samples of cheeses and dairy environments. In conclusion, L. monocytogenes has the ability to persist in the environment of dairy products by forming biofilms in several inert surfaces such as stainless steel, rubber and silicone, which may represent a continuing source of contamination to manufacture processes of dairy products.

Submitted by TATIANA CAMACHO CHEREGATTO null (taticheregatto@gmail.com) on 2016-02-20T01:37:01Z No. of bitstreams: 1 Dissertação final.pdf: 2331480 bytes, checksum: ca47895978f20b5cf422aae38a0c22a9 (MD5) / Approved for entry into archive by Juliano Benedito Ferreira (julianoferreira@reitoria.unesp.br) on 2016-02-22T20:28:30Z (GMT) No. of bitstreams: 1 cheregatto_tc_me_rcla.pdf: 2331480 bytes, checksum: ca47895978f20b5cf422aae38a0c22a9 (MD5) / Made available in DSpace on 2016-02-22T20:28:30Z (GMT). No. of bitstreams: 1 cheregatto_tc_me_rcla.pdf: 2331480 bytes, checksum: ca47895978f20b5cf422aae38a0c22a9 (MD5) Previous issue date: 2015-12-15 / Os refrigerantes são bebidas gaseificadas, obtidas através da diluição do suco ou extrato vegetal de sua origem em água potável, adicionada de açúcares. Devido ao elevado teor de açúcar neste produto e ao baixo pH, os refrigerantes tornam-se propícios ao desenvolvimento de microrganismos, em especial as leveduras. A contaminação microbiológica é mais comum na etapa de produção, entretanto, a maioria dos contaminantes pode ser proveniente de matérias-primas como água ou equipamentos quando não higienizados de maneira adequada. De acordo com o histórico de análises microbiológicas da Indústria BEBIDAS POTY Ltda, foram detectados alguns pontos de contaminação por leveduras dentro do fluxograma de produção, as quais têm apresentado certa resistência aos sanificantes utilizados. Desta forma o presente trabalho teve como objetivo isolar, identificar leveduras de matérias primas e diversos equipamentos da produção e avaliar o efeito inibitório dos sanificantes nas leveduras isoladas, buscando conhecer a eficácia dessas preparações. Neste estudo, foram isoladas 26 leveduras apenas da água de enxágue após o processo de higienização dos equipamentos de produção em todas as linhas de produtos carbonatados. Dentre as leveduras isoladas, os gêneros mais comuns foram Candida tropicalis, C. orthopsilosis, C. viswanathii, C. boidinii, Pichia manshurica, Zygosaccharomyces bisporus, sendo a espécie C. sojae a mais frequente. Os isolados foram testados na presença de 1) detergente alcalino clorado, 2) detergente alcalino não clorado, 3) desinfetante ácido peracético e 4) base ácida com ação de detergência/desinfetante de duas marcas comerciais identificadas como Marca I e Marca II, na perspectiva de encontrar a concentração mínima inibitória. Os agentes químicos de basicidade elevada com ação de limpeza foram os mais eficientes nos testes de inibição/crescimento e o menos eficazes foram os detergentes alcalinos contendo cloro sendo necessária a utilização de concentrações muito elevadas para atingir a concentração mínima inibitória. Os agentes químicos com ação de desinfecção demonstraram que as leveduras, foram muito sensíveis para os ácidos fortes oxidantes como o nítrico, peracético e gás O3. / Soft drinks are carbonated beverages, obtained by diluting the juice or vegetable extract in drinking water, added of sugars. Because of the high sugar content of this product and the low pH, the refrigerants are susceptible to development of microorganisms, in particular yeasts. Microbial contamination is most common in the production step, however, most of the contaminants can come from raw materials and equipment such as water when not cleaned properly. According to the history of microbiological analyzes of Industry DRINKS POTY Ltda, some points of contamination by yeasts were detected within the production flow chart, which have shown some resistance to the sanitizers used. Thus, the present study aims to isolate and identify yeast from raw materials and from various equipment and evaluate the inhibitory effect of sanitizers on yeasts. It was isolated 26 yeasts strains from rinse water after the process of cleaning production equipment in all lines of carbonated products. Among the yeasts, the most common genera were Candida tropicalis. C. orthopsilosis, C. viswanathii, C. boidinii, Pichia manshurica, Zygosaccharomyces bisporus, the most frequent species was C. sojae. The isolates were tested in the presence of 1) chlorinated alkaline detergent, 2) alkaline detergent non-chlorinated, 3) disinfectant peracetic acid and 4) acid based detergent with disinfectant action two trademarks identified as Marca I and Marca II with a view to find the minimum inhibitory concentration. Chemical agents with high alkalinity were the most efficient in inhibition of yeast growth the less effective was alkali detergent containing chlorine being necessary to use very high concentrations to achieve the minimum inhibitory action. The data showed that the yeasts were very sensitive, to oxidizers such as nitric acid, peracetic acid and O3 gas.

O objetivo do presente estudo foi avaliar a capacidade de isolados de Listeria monocytogenes em formar biofilmes em superfícies inertes, bem como sua resistência a agentes sanitizantes. Foram utilizados 37 isolados provenientes de ambiente de laticínios, amostras de queijos e salmoura, pertencentes à coleção do Laboratório de Microbiologia e Micotoxicologia de Alimentos (LMMA) do Departamento de Engenharia de Alimentos da FZEA/USP. Dos 37 isolados avaliados, 67,6% eram pertencentes ao sorotipo 4b. Três isolados de L. monocytogenes foram obtidos de salmoura, 5 foram obtidos de caixas plásticas, 1 de queijo Prato, 1 da mão de manipulador de embalagens, e 27 foram isolados de superfícies sem contato com alimentos (piso da sala de pasteurização, piso da câmara fria, ralo da câmara fria ou estrado da câmara fria). Os isolados de L. monocytogenes apresentaram maior capacidade de produzir biofilme nos ensaios com cupons de aço inox (43,2% dos isolados), seguido dos ensaios em microplaca de poliestireno (16,2%), cupons de borracha (13,5%) e discos de silicone (2,7%). As células de L. monocytogenes aderidas nas superfícies do aço inox foram visualizadas sob microscopia eletrônica de varredura após 48 horas de incubação a 37ºC. Dezenove isolados de L.monocytogenes, os quais produziram biofilmes nos ensaios com aço inox, borracha ou silicone, foram testados para determinação da eficiência de sanitizantes pelo método de concentração inibitória mínima (CIM), utilizando-se ácido peracético (2%), cloreto de banzalcônio (1%), digluconato de clorexidina (2%), hipoclorito de sódio (2%) e tintura de iodo (2%). Os isolados de L. monocytogenes analisados apresentaram resistência a ácido peracético, hipoclorito de sódio e tintura de iodo, cujos valores de CIM foram 3,12%, 6,25% e 6,25%, respectivamente. Nenhum isolado apresentou resistência a cloreto de benzalcônio e digluconato de clorexidina, os quais foram eficientes para inibição de isolados de L. monocytogenes provenientes de amostras de queijos e ambientes de laticínios. A L. monocytogenes apresenta capacidade de persistir em ambiente de laticínios sob a forma de biofilme em várias superfícies inertes como aço inox, borracha e silicone, o que pode representar uma fonte permanente de contaminação para produtos e processos de obtenção de leite e derivados. / The objective of the present study was to evaluate the ability of isolates of Listeria monocytogenes to form biofilms and their resistance to sanitizers. Thirty seven strains belonging to the collection of the Laboratory of Microbiology and Food Mycotoxicology (LMMA), Department of Food Engineering of FZEA / USP, were used. Of the 37 isolates, 67.6% belonged to serotype 4b. Three isolates of L. monocytogenes were obtained from brine, 5 were obtained from plastic boxes, one of Prato cheese, one from the packaging handler\'s hand, and 27 were isolated from non-food contact surfaces (pasteurization room floor, the floor of the cold room, the drain cold or pallet from the cold chamber). The isolates of L. monocytogenes showed greater ability to produce biofilm in the assays with stainless steel coupons (43.2% of isolates), followed by polystyrene micro plate (16.2%), rubber coupons (13.5%) and silicone disks (2.7%) assays. Cells of L. monocytogenes attached to stainless steel surfaces were viewed under scanning electron microscopy after 48 hours incubation at 37°C. Nineteen strains of L. monocytogenes, which were considered biofilms producers in the assays with stainless steel, rubber or silicone, have been tested to evaluate the efficiency of the sanitizing method by means of the minimum inhibitory concentration (MIC), using peracetic acid (2%), sodium chloride benzalkonium (1%), chlorhexidine digluconate (2%), sodium hypochlorite (2%) and iodine solution (2%). The isolates of L. monocytogenes analyzed showed resistance to peracetic acid, sodium hypochlorite and iodine tincture, with MIC values of 3.12%, 6.25% and 6.25%, respectively. No isolate showed resistance to benzalkonium chloride and chlorhexidine digluconate, which were effective for inhibiting the isolates of L. monocytogenes from samples of cheeses and dairy environments. In conclusion, L. monocytogenes has the ability to persist in the environment of dairy products by forming biofilms in several inert surfaces such as stainless steel, rubber and silicone, which may represent a continuing source of contamination to manufacture processes of dairy products.

Submitted by Biblioteca da Faculdade de Farmácia (bff@ndc.uff.br) on 2017-04-07T17:48:18Z No. of bitstreams: 1 José, Kelly Fernanda Campos [Dissertação, 2014].pdf: 955086 bytes, checksum: 84564fe3de6240b8248fb1dbad2cf5ec (MD5) / Made available in DSpace on 2017-04-07T17:48:18Z (GMT). No. of bitstreams: 1 José, Kelly Fernanda Campos [Dissertação, 2014].pdf: 955086 bytes, checksum: 84564fe3de6240b8248fb1dbad2cf5ec (MD5) / O pescado é um alimento de excelente valor nutritivo devido às suas vitaminas, proteínas e ácidos graxos insaturados, no entanto, pode veicular uma variedade de microrganismos patogênicos ao homem, aumentando a preocupação com a qualidade sanitária. Nesse contexto, a formação de biofilme na indústria de alimentos representa uma preocupação por sua potencialidade em resistir a tratamentos sanitizantes, além da possibilidade de perda da qualidade por deterioração e/ou veiculação de patógenos, justificando assim, a importância de uma correta higienização na indústria. Neste estudo objetivou-se identificar microrganismos presentes nas superfícies de processamento de pescado, assim como avaliar a capacidade de formação de biofilmes bacterianos em equipamentos e sinalizar maneiras de evitar sua formação. Para tal, foi realizada a avaliação de superfícies através do método “swab”, com coleta de amostras das superfícies do tanque de lavagem, esteira de evisceração e descabeçamento e tanque de armazenamento de molho de cobertura, em uma indústria de pescado do Estado do Rio de Janeiro, através de três visitas aleatórias realizadas em diferentes meses do ano. As referidas amostras foram encaminhadas sob refrigeração para o Laboratório de Higiene e Microbiologia de Alimentos da Faculdade de Farmácia – UFF, onde foram processadas conforme métodos e recomendações oficiais. Em relação aos resultados foram constatadas não conformidades na lista de verificação, com situação mais crítica observada no item manipuladores. Na análise bacteriológica evidenciou-se elevadas contagens de bactérias heterotróficas aeróbias mesófilas, presença de Salmonela spp., Listeria spp., Bacillus spp., coliformes totais e Escherichia coli. Demonstrou-se capacidade de formação de biofilme por cepas de E. coli isoladas nas três visitas realizadas. Na avaliação da eficácia de sanitizantes de uso industrial, foram observados melhores resultados na exposição à biguanida polimérica e taxas elevadas de resistência ao quaternário de amônio. Diante dos resultados, constatou-se ausência de condições higiênico-sanitárias adequadas e circunstâncias propícias para formação de biofilmes bacterianos / Fish is a food of great nutricional value due to their vitamins, proteins and unsaturated fatty acids, however, can convey a variety of pathogenic microorganism to man increasing the concern about ensuring health standards. In this context, the formation of biofilms in the food industry represent a preoccupation because of its potencial to resist sanitizing treatments, besides the possibility of causing quality loss due to deterioration and/or transmission of pathogens, justifying the importance of proper hygiene in industry. This study aimed to identify microorganisms present on the surfaces of fish processing and assess the ability of formation of microbial biofilms on equipament and to signal ways to avoid their formation. In this sense, the evaluation of surfaces contact was performed from samples collected on the surfaces of the washing tank, gutting and beheading mat and of storing tank coverage sauce, at seafood industry in a state of Rio de Janeiro, through three randomized visits in different months of the year. These samples were sent under refrigeration to the Laboratory of Food Microbiology and Hygiene, Faculty of Pharmacy – UFF, which were processed by methods and official recommendations. Regarding the results, non-conformities were found by checklist, with more critical situation in the item handlers. Bacteriological analysis revealed a high count of aerobic mesophilic, presence of Salmonella spp., Listeria spp., Bacillus spp., total coliforms and Escherichia coli. It was demonstrated ability of biofilm formation by strains of E.coli isolated in three visits. In evaluating the effectiveness of sanitizers industrial use was observed better results in exposure to polymeric biguanide and high rates resistance to quaternary ammonium. Considering the results, it has been found a lack of adequate sanitary conditions and circumstances conducive to the formation of bacterial biofilms

Three studies regarding Escherichia coli O157:H7 in apple cider were conducted. The objectives were: to evaluate the effectiveness of wash and sanitizers for removing E. coli O157:H7 from apples; to survey cider producer practices; and to determine the efficacy of ultraviolet light for reducing E. coli O157:H7 in cider. Apples with a five-strain acid resistant mixture of E. coli O157:H7 were treated with 200 ppm hypochlorite, a phosphoric acid-based fruit wash, 5% acetic acid, 5% acetic acid followed by 3% hydrogen peroxide, a peroxyacetic acid-based solution, and distilled water. The water wash caused insignificant reductions. All other treatments caused significant reductions. Acetic acid and peroxyacetic acid were the most effective with reductions of 3.1 and 2.6 logs, respectively. The survey determined that most producers are small, seasonal operations. Most use sound orchard management practices, clean and sanitize daily, sort and wash apples, use refrigeration, and try to prevent contamination. However, some use drop and damaged apples. Few use chemical sanitizers on apples, preservatives, pasteurize cider, or have HACCP programs. Cider inoculated with the same mixture of E. coli O157:H7 was processed using a thin- film ultraviolet disinfection unit operating at 254 nm. Dosages ranged from 9,402 to 61,005 æW- sec/cm2. Treatment significantly reduced E. coli O157:H7 (pó 0.0001) with a mean reduction of 3.81 log CFU/ml. Reduction was also affected by the level of background microflora in cider. Results indicate that ultraviolet light can reduce this pathogen in cider. However, additional reduction measures are necessary to achieve the required 5 log reduction. / Master of Science

No description available.

Master of Science / Food Science / Kelly J. K. Getty / Dry-processing environments are particularly challenging to clean and sanitize because water introduced into systems not designed for wet cleaning can favor growth and establishment of pathogenic microorganisms such as Salmonella. The objective was to determine the efficacy of isopropyl alcohol quaternary ammonium (IPAQuat) formula and carbon dioxide (CO[subscript]2) sanitizer system for eliminating Enterococcus faecium and Salmonella on food contact surfaces. Coupons of stainless steel and conveyor belting material used in dry-processing environments were spot-inoculated in the center of 5 × 5 cm coupons with approximately 7.0 log CFU/ml of E. faecium and up to 10 log CFU/ml of a six-serotype composite of Salmonella and subjected to IPAQuat-CO[subscript]2 sanitation treatments using exposure times of 30 s, 1 or 5 min. After sanitation treatments, wet coupons were swabbed for post-treatment survivors. Preliminary experiments included coupons which were soiled with a flour and water solution prior to inoculation and subsequent sanitation treatments. For the main study, inoculated surfaces were soiled with a breadcrumb flour blend and allowed to sit on the lab bench for a minimum of 16 h before sanitation. Preliminary results showed that IPAQuat-CO[subscript]2 sanitizing system was effective in reducing approximately 3.0 logs of E. faecium and Salmonella from clean and soiled surfaces after 1 min exposure but higher initial inoculum levels were needed to demonstrate >5 log reductions. For the main study, pre-treatment Salmonella populations were approximately 7.0 log CFU/25 cm[superscript]2 and post-treatment survivors were 1.3, < 0.7 (detection limit), and < 0.7 log CFU/25 cm[superscript]2 after 30 s, 1 or 5 min sanitizer exposures, respectively, for both clean and soiled surfaces. Treatment with IPAQuat-CO[subscript]2 sanitation system using 30 s sanitizer exposures resulted in 5.7 log CFU/25 cm[superscript]2 reductions whereas, greater than 6.0 log CFU/25 cm[superscript]2 reductions were observed for sanitizer exposures of 1 and 5 min. The IPAQuat-CO[subscript]2 sanitation system reduced 6 logs CFU/25 cm[superscript]2 of Salmonella with sanitizer exposure times of at least 1 min. The IPAQuat-CO[subscript]2 system would, therefore, be an effective sanitation system to eliminate potential contamination from Salmonella on food contact surfaces and have application in facilities that process dry ingredients or low-moisture products.

O Bacillus cereus é um patógeno amplamente distribuído na natureza, relacionado a intoxicações alimentares e causador da coagulação doce do leite. A intoxicação pode ocorrer após a ingestão de alimentos nos quais a bactéria produziu a toxina. Em laticínios, o B. cereus é problemático por sua habilidade de formar esporos resistentes ao calor e sobreviver aos tratamentos térmicos, como a pasteurização e UHT. As espécies de Bacillus são freqüentemente isoladas de leite pasteurizado e UHT e evidências indicam que os biofilmes formados nas superfícies dos equipamentos de processamento são uma das principais fontes de contaminação. No biofilme, as células ou esporos aderidos, têm aumentada sua resistência e podem resistir ao processo de sanificação, se tornando focos de disseminação de bactérias no processo. A matriz polimérica do biofilme reage e neutraliza os agentes sanificantes, expondo as bactérias em seu interior a doses subletais, podendo levar a aquisição de resistência. Neste estudo, biofilmes de células vegetativas B. cereus foram desenvolvidos na superfície de aço inoxidável, tipo 304, com filme de condicionamento de leite. A adesão média das células foi de 1,4 x 105UFC/cm2. Também foram desenvolvidos biofilmes de esporos, com adesão média em aço inoxidável de 1,4 x 104UFC/cm2. Foi avaliada a resistência das células vegetativas e esporos de B. cereus em biofilmes, ao processo simulado de higienização por clean in place (CIP) realizado em laticínios. Após a limpeza a adesão das células vegetativas em aço inoxidável foi reduzida a aproximadamente 1CFU/cm2. Após a sanificação, os resultados permaneceram inalterados. A contaminação remanescente foi relacionada com a maior resistência das células nos biofilmes formados. Após a limpeza e sanificação a adesão média dos esporos foi de 8,9 x 101 UFC/cm2 e 3,3 x 101 UFC/cm2, respectivamente. Tendo em vista este resultado, foi observado que esporos de B. cereus são mais difíceis de remover de superfícies de aço inoxidável do que células vegetativas, com procedimentos CIP. Finalmente, foi realizada a exposição de células vegetativas de B. cereus a três concentrações subletais (3,9; 1,8 e 0,9µg/mL) de cloreto de alquil amidopropil dimetil benzil amônio para avaliação da adaptação pelo método da concentração inibitória mínima (CIM). A aquisição de resistência foi avaliada pela comparação do valor inicial de CIM (7,4µg/mL), com os valores finais, após 28 dias de exposição. Após o período de adaptação, o valor de CIM encontrado foi o dobro do original (14,9µg/mL) indicando aquisição de resistência ao sanificante pela cepa. Foi constatado ainda que o cultivo da cepa na menor concentração subletal apresentou resultados mais coerentes, sugerindo que exposição a doses subletais mais brandas resulta em uma maior resposta adaptativa. / Bacillus cereus is a pathogen widely distributed in the environment and a serious problem in the dairy industry because of its ability to form heat-resistant spores that can survive pasteurization and UHT treatments. This bacteria is responsible for foodborne diseases in man due to production of toxins that may cause gastroenteritis, diarrhoea and vomiting. In addition, B. cereus is responsible for spoilage of pasteurized milk and cream referred to as \"sweet curdling\". Bacillus strains are frequently isolated from pasteurized and UHT treated milk and evidence indicates that biofilm formed on processing equipment surfaces are major sources of milk contamination. In biofilms, adherent cells and spores acquire increased resistance and persist to the sanitization process, becoming sources of bacteria dissemination in food processing. The extracellular polymeric matrix neutralizes the sanitizing agents and exposing the bacteria in biofilms to sublethal concentrations can lead to an increased resistance. In this study, biofilms of B. cereus vegetative cells were developed in a 304 stainless steel (SS) surface with a milk conditioning film. The mean adhesion of cells on SS surface was 1.4 x 105CFU/cm2. Biofilms of B. cereus spores were also developed, and the mean adhesion found was 1.4 x 104CFU/cm2. The resistance of B. cereus vegetative cells and spores in biofilms to a simulated clean-in-place (CIP) procedure used in dairy industry was evaluated. After cleaning procedure, the population of vegetative cells in the SS surface was reduced to approximated 1 CFU/cm2. After sanitizing procedure, the cell count remained unaltered. The remaining contamination was related with the increased resistance of cells in the developed biofilms. After cleaning and sanitizing procedures, the mean of spore adhesion found was 8.9 x 101 CFU/cm2 and 3.3 x 101 CFU/cm2, respectively. These results show that B. cereus spores are more difficult to remove from SS surfaces than vegetative cells using CIP procedures. Finally, B. cereus vegetative cells were exposed to three different sublethal concentrations (3.9; 1.8 and 0.9µg/mL) of alkyl amidopropyl dimethyl benzyl ammoniun cloride, for evaluation of adaptation, using the Minimum Inhibitory Concentration (MIC) test. The acquired resistance was evaluated by comparing the initial MIC value (7.4µg/mL) with final MICs, after 28 days of exposure. After the adaptation period, with exception of an experiment where the MIC was threefold the original value (29.8µg/mL), in the other experiments the MICs found was double (14.9µg/mL) of the original MIC, indicating acquisition of resistance by the B. cereus strain. It was observed that the growth of cells in the mildest sublethal concentration (0.9µg/mL) resulted in more consistent effects, suggesting that the exposure to mildest sublethal concentrations results in higher adaptive responses.

Nosocomial infections are acquired in health care settings and they can lead to catastrophic health care consequences for patients. These infections can also pose significant financial burdens on society and health care systems. Educating nurses on hand hygiene is essential to reducing infection rates. The research question for the study examined the effectiveness of hand hygiene among nurses in reduction of nosocomial infections and how can health care organizations develop educational strategies to reduce nosocomial infections to improve public confidence in health care systems. The purpose of this study was to educate nurses on how to reduce the incidence of nosocomial infections. The evidence-based practice model for this project was Florence Nightingale's environmental theory. The health belief model was used to identify the reasons for health care culture and how they inspire change. In this study, 2 licensed practical nurses and 2 registered nurses were educated on how to reduce nosocomial infections in acute care settings. Participants then completed a questionnaire to assess their knowledge of hand hygiene as a means of reducing nosocomial infections when caring for patients. All participants agreed that hand hygiene; reduces the risk of contracting a nosocomial infection, suggesting that the incidence of nosocomial infections within acute care settings maybe reduced through this education. This project has potential positive social change by educating first and second year nursing students on the importance of hand hygiene in reduction of nosocomial infections and preventing patients from sustaining further injuries while admitted in acute care settings.