Hazards in non-pasteurized milk on retail sale in Brazil: prevalence of Salmonella spp, Listeria monocytogenes and chemical residues

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

The effects of Chlorella vulgaris in the protection of mice infected with Listeria monocytogenes. Role of natural killer cells

In this work we have demonstrated the effects of oral administration of Chlorella vulgaris (CV) on Natural Killer cells (NK) activity of mice infected with a sublethal dose of viable Listeria monocytogenes. The treatment with C. vulgaris produced a significant increase on NK cells activity in normal (non-infected) animals compared to the animals that received only vehicle (water) (p < 0.0001). Similarly, the infection alone produced a significant increase on NK cells activity, which was observed at 48 and 72 hours after the inoculation of L. monocytogenes. Moreover, when CV was administered in infected animals, there was an additional increase in NK cells activity which was significantly higher than that found in the infected groups (p < 0.0001) CV treatment (50 and 500mg/Kg) of mice infected with a dose of 3x105 bacteria/animal, which was lethal for all the non- treated controls, produced a dose-response protection which led to a 20% and 55% survival, respectively (p < 0.0001).

Ocorrência de Listeria spp. e de Listeria monocytogenes, em um matadouro-frigorífico de bovinos do estado de São Paulo

We evaluated the presence of Listeria spp. and Listeria monocytogenes in environmental samples by means of swabs collected the bovine slaughter plant enabled to export, located in the state of Sao Paulo, Brazil. After the pre-enrichment at 30±1°C for 22 to 26h the samples were analyzed using the BAX System Listeria. Those positive for Listeria spp. were submitted a second PCR reaction to confirm the presence of Listeria monocytogenes. From 411 environmental samples analyzed, 62 (15.1%) were positive for Listeria spp. and 21 (5.1%) for Listeria monocytogenes, which showed their persistence in the slaughter plant. There were no statistical differences between the rainy and dry periods and between areas sampled, although it has been found between sectors. The floor surface and the sector cuts have higher rates of positivity.

Production of biofilm by Listeria monocytogenes in different materials and temperatures

Listeria monocytogenes, considered as one of the most important foodborne pathogens, is easily found on surfaces, particularly in the form of a biofilm. Biofilms are aggregates of cells that facilitate the persistence of these pathogens in food processing environments conferring resistance to the processes of cleaning and may cause contamination of food during processing, thus, representing a danger to public health. Little is known about the dynamics of the formation and regulation of biofilm production in L.monocytogenes, but several authors reported that the luxS gene may be a precursor in this process. In addition, the product of the inlA gene is responsible for facilitating the entry of the microorganism into epithelial cells that express the receptor E-cadherin, also participates in surface attachment. Thus, 32 strains of L.monocytogenes isolated from different foods (milk and vegetables) and from food processing environments were analyzed for the presence of these genes and their ability to form biofilms on three different surfaces often used in the food industry and retail (polystyrene, glass and stainless steel) at different temperatures (4, 20 and 30°C). All strains had the ilnA gene and 25 out of 32 strains (78.1%) were positive for the presence of the luxS gene, but all strains produced biofilm in at least one of the temperatures and materials tested. This suggests that genes in addition to luxS may participate in this process, but were not the decisive factors for biofilm formation. The bacteria adhered better to hydrophilic surfaces (stainless steel and glass) than to hydrophobic ones (polystyrene), since at 20°C for 24h, 30 (93.8%) and 26 (81.3%) produced biofilm in stainless steel and glass, respectively, and just 2 (6.2%) in polystyrene. The incubation time seemed to be an important factor in the process of biofilm formation, mainly at 35°C for 48h, because the results showed a decrease from 30 (93.8%) to 20 (62.5%) and from 27 (84.4%) to 12 (37.5%), on stainless steel and glass, respectively, although this was not significant (. p=0.3847). We conclude that L.monocytogenes is capable of forming biofilm on different surfaces independent of temperature, but the surface composition may be important factor for a faster development of biofilm. © 2013 Elsevier Ltd.

Produção de biofilme por Listeria monocytogenes isoladas de diferentes alimentos

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Efeitos do ultrassom de alta intensidade sob pressão na redução de Listeria monocytogenes em extrato de carne bovina

Pós-graduação em Engenharia e Ciência de Alimentos - IBILCE

Prevalência de Listeria monocytogenes, Escherichia coli O157, Salmonella spp. e micro-organismos indicadores de contaminação em bovinos abatidos em estabelecimento de exportação

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Isolamento e enumeração de Listeria monocytogenes em produtos cárneos comercializados no varejo da região de Botucatu, SP

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Ocorrência de Listeria monocytogenes em frangos alternativos

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Listeria monocytogenes, E. coli O157, Salmonella spp. e microrganismos indicadores em carcaças bovinas para exportação

Samples were collected from 100 carcasses in a slaughterhouse exporter, located within the State of São Paulo, sampled over a year through the sponge method, applied to the chest of the animal. Samples were taken at three points, denominated A, B and C, each carcass sampled at three points located in the following steps: after bleeding (A) after skinning (B) and after washing (C). Research was conducted for Listeria sp., E. coli O157, Salmonella spp. and Micro-organism (Petrifilms ® AC, EC and EB). Listeria or E. coli O157 were not isolated in any of the 300 samples. Salmonella spp. was isolated in nine, eight at point A and one at point B. For Mesophiles, scores ranged from 0 to 6.8 log UFC/cm²; for Total coliforms, 0 to 4.57 log UFC/cm² and E. coli from 0 to 4.38 log UFC/cm². With the results obtained and compared with the literature, it is concluded that the establishment in this study has both sanitary quality (due to the low prevalence of pathogens) and hygienic quality (due to the sharp decrease in the microbial load of indicators along the line.

Alterações químicas e microbiológicas nas silagens de capim-Tifton 85 após a abertura dos silos

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Activity of disinfectants against foodborne pathogens in suspension and adhered to stainless steel surfaces

The purpose of this study was to investigate and compare the efficacy of various disinfectants on planktonic cells and biofilm cells of Listeria monocytogenes, Staphylococcus aureus and Escherichia coli. Numbers of viable biofilm cells decreased after treatment with all tested disinfectants (iodine, biguanide, quaternary ammonium compounds, peracetic acid and sodium hypochlorite). Sodium hypochlorite was the most effective disinfectant against biofilm cells, while biguanide was the least effective. Scanning electron microscopy observations revealed that cells adhered on stainless steel surface after treatment with the disinfectants. No viable planktonic cells were observed after treatment with the same disinfectants. Based on our findings, we concluded that biofilm cells might be more resistant to disinfectants than plancktonic cells.

Essential Oils Against Foodborne Pathogens and Spoilage Bacteria in Minced Meat

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Surfactin reduces the adhesion of food-borne pathogenic bacteria to solid surfaces

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)