Biofilm-producing ability of Listeria monocytogenes isolates from Brazilian cheese processing plants.

The persistence of Listeria monocytogenes in food industry environments has been associated to the ability of specific isolates to produce biofilms. This study aimed to evaluate the biofilm production of 85 L. monocytogenes strains previously isolated from samples of cheese, brine and the environment of two cheese processing plants located in São Paulo, Brazil. The L. monocytogenes isolates belonged to serotypes 4b, 1/2b and 1/2c, yielded 30 different pulsotypes by pulsed-field gel electrophoresis (PFGE), and were submitted to biofilm-formation assays on polystyrene microplates and stainless steel coupons incubated statically at 35±0.5°C for 48h. All isolates from different sources showed ability to produce biofilms on polystyrene microplates, from which 21 (24.7%) also produced biofilms on stainless steel. Four isolates (4.7%) belonging to four different pulsotypes were classified as strong biofilms-producers on polystyrene microplates, while isolates belonging to four pulsotypes previously evaluated as persistent had weak or moderate ability to produce biofilms on polystyrene microplates. No relationship between the serotypes or pulsotypes and their biofilm-forming ability was observed. This study highlights the high variability in the biofilm production among L. monocytogenes strains collected from cheese and cheese-production environment, also indicating that strong biofilm-formation ability is not a key factor for persistence of specific isolates in cheese processing plants.

Microbiological quality of finger food and snacks / Qualidade microbiológica de lanches e salgados

Although finger food is convenient, it may be easily contaminated from the stage of preparation to the moment of consumption. This study aimed at evaluating the microbiological quality of finger food and sandwiches sold in Botucatu SP, Brazil, by following the standards established by the Brazilian Health Surveillance Agency, ANVISA. The analysis was conducted according to APHA. A hundred and twenty-two samples of meat, chicken, shrimp, cheese, and vegetable finger food and sandwiches were tested from August 2008 to March 2009. Seventeen (13.9 %) samples of meat, cheese, vegetables and chicken were in disagreement with the ANVISA standards some of them in more than one parameter. High counting of thermotolerant coliforms and coagulase-positive staphylococci were found in ten (8.2 %) and eight (6.5 %) samples, respectively. Salmonella spp. was detected in two samples (1.6 %). No Bacillus cereus and sulfite-reducing clostridia were isolated. Although only 10 samples (8.2 %) showed pathogenic bacteria contamination, these results are relevant, since they indicate that the population is generally exposed to risks of acquiring foodborne diseases. Thus, the sanitary authorities might implement actions for supervising the quality of the food sold in Botucatu, and to strengthen the food sellers to improve the hygienic conditions and be aware of the risks of food contamination.

Neste trabalho foi avaliada a qualidade microbiológica de salgados e sanduíches comercializados em Botucatu-SP, seguindo-se a legislação em vigor. As análises foram realizadas de acordo com APHA. Foram analisadas 122 amostras de salgados de carne, frango, camarão, queijo e vegetais, e sanduíches no período de agosto/2008 a março/2009. Dezessete (13,9 %) amostras de carne, queijo, vegetais e frango, e em algumas em mais de um parâmetro, estavam em desacordo com a legislação em vigor. Foram detectadas elevadas contagens de coliformes termotolerantes e estafilococos coagulase-positiva, respectivamente, em dez (8,2 %) e oito (6,5 %) amostras. Salmonella spp. foi isolada em duas amostras (1,6 %). As contagens de Bacillus cereus e de Clostrídio Sulfito Redutor não ultrapassaram os padrões da legislação. A maioria dos salgados mostrou resultados dentro dos padrões estabelecidos pela legislação. A presença de bactérias patogênicas como S. aureus e Salmonella spp. foi demonstrada em 10 amostras (8,2 %); e este resultado é relevante, pois indica que a população está exposta a riscos de doenças veiculadas por alimentos. Torna-se necessário colocar em prática a vigilância dos alimentos comercializados em Botucatu, incentivar a melhoria de condições de higiene pelos comerciantes, e ter ciência dos riscos e das implicações da contaminação microbiológica dos alimentos.