Detection of pathogenic Escherichia coli and microbiological quality of chilled shrimp sold in street markets.

UNLABELLED: Foodborne illnesses caused by Escherichia coli are one of the most important gastrointestinal diseases and therefore represent a public health risk. The presence of E. coli in water or in products such as shrimp indicates faecal contamination. However, indicator micro-organisms can be used to evaluate the microbiological quality of food sold in markets. This study focused on detecting isolates of E. coli containing the genes stx1A, stx2A, eae, LTI, STa, STb, aggR and pCVD432 in chilled shrimp sold in street markets in the municipality of São Paulo, Brazil, and to assess the microbiological quality of this product. Enteropathogenic and enterotoxigenic E. coli pathotypes were detected on the surface of two chilled shrimp samples. Salmonella spp. was not isolated. In addition, contamination of surface and muscle of the shrimp samples was found to be correlated. The detection of EPEC and ETEC pathotypes in chilled shrimp sold in street markets in Brazil provides useful epidemiological information for public health authorities to improve food safety and public health. SIGNIFICANCE AND IMPACT OF THE STUDY: Shrimps are crustaceans commonly produced and consumed in Brazil. Specimens of Farfantepenaeus brasiliensis and Litopenaeus schmitti sold in street markets were examined by PCR to detect the presence of Escherichia coli pathotypes (enteropathogenic, enterotoxigenic, enterohemorrhagic and enteroinvasive). EPEC and ETEC strains were detected in whole shrimp. These findings provide useful information for public health authorities to improve the food safety and health of the Brazilian population.

Shiga toxigenic and enteropathogenic Escherichia coli in water and fish from pay-to-fish ponds.

UNLABELLED: Escherichia coli is part of the normal microflora of the intestines of mammals. However, among the enteric pathogens, it is one of the leading causes of intestinal diseases, especially Shiga toxigenic E. coli, which can cause diarrhoea, haemorrhagic colitis and complications like haemolytic uraemic syndrome and thrombotic thrombocytopaenic purpura. Escherichia coli is considered a serious public health problem. Water and fish samples were subjected to biochemical tests to confirm the presence of E. coli and by PCR to verify the presence of pathogenic strains (O157, enteropathogenic and shiga toxigenic) in water and fish (skin, gastrointestinal tract and muscles) from pay-to-fish ponds located in the Córrego Rico watershed in the northeastern region of the state of São Paulo, Brazil. Of the 115 E. coli isolates from fish or water, five (4·34%) contained eae and stx2 genes, one had only the eae gene and two had the stx1 gene. An isolate containing the stx2 gene was also found in the water sample. In addition, eight isolates (6·95%) from the fish gastrointestinal tract contained rfbEO157:H7 (O157 gene), and three (2·61%) contained stx2 and eae genes, demonstrating the potential risk to the environment and public health. The results provide useful basic information for the proper management of these environments and animals in order to prevent faecal pollution, reducing health risks to the Brazilian population. SIGNIFICANCE AND IMPACT OF THE STUDY: Pay-to-fish ponds are a common commercial activity in Brazil. Samples of water and Oreochromis niloticus were examined by PCR to detect the presence of pathogenic strains of Escherichia coli (O157, enteropathogenic and shiga toxigenic). Several pathogenic strains were detected in this study, providing useful epidemiological information for the proper management of these environments and animals in order to prevent faecal pollution, reducing health risks to the Brazilian population.

Influence of chlorine added to drinking water during the preslaughter feed withdrawal on microbiology and morphology of the broiler gastrointestinal tract.

The objective of this experiment was to test the effects of the addition of chlorine to broiler drinking water during a 12-h preslaughter feed withdrawal period on reduction of the quantities of microorganisms, such as Escherichia coli and enterococci, in broiler crops and ceca. Reduction of these microorganisms would likely also reduce contamination of broiler meat by pathogenic bacteria during processing. It was also investigated if the chlorine caused some intestinal damage that could disseminate the microorganisms to the carcass. A total of 40 Cobb male broilers were used. Samples of crop and cecal content were collected for microbiological analysis, and duodenum and jejunum were used for morphological analysis from 10 birds in each treatment. The most probable number (MPN) of E. coli and enterococci in the collected samples of crop and ceca and the measure of the free residual chlorine in water were determined. The scanning electron microscopy from duodenum and jejunum was used to illustrate the mucosa integrity. The chlorine added to water was efficient in reducing the quantities of microorganisms in broiler crops and improved the integrity of the mucosa. Therefore, preslaughter feed withdrawal should be coupled with crop disinfection, because preslaughter feed withdrawal increases the MPN of enterococci and E. coli in broiler crops. So, it presents a higher risk for carcass contamination during slaughterhouse processing and, consequently, a higher risk for public health.