Determination and characterization of pathogens found in dairy products

ABSTRACT

The quality of dairy products was investigated on 63 samples, being 24 non industrial-type ice creams, 19 pasteurized milk creams and 20 of cheese pâtés. The samples were analyzed for searching thermo-tolerant coliforms, coagulase positive Staphylococcus, Salmonella spp., molds and yeasts, Bacillus cereus and Listeria monocytogenes. Additionally, characterization of the enterotoxigenic potential of B. cereus for the codified genes of enterotoxins NHE and HBL was also carried out by PCR technique; also the molecular subtypingof L. monocytogenes allelic polymorphism of virulence genes actA and hly was performed. Thirty-three percent (8/24) of ice cream samples and 15.8% (3/19) of milk cream samples did not comply with the microbiological standards established by RDC Nº12/2001 of ANVISA, because these products showed thermo-tolerant coliform counts above the established limits. L. monocytogenes was detected in one milk cream sample and those bacteria isolates were identified as belonging to the lineage I, which is potentially pathogenic to human. Potentially enterotoxigenic B. cereus was isolated from the three kinds of products analyzed in the present study. The degree of microbiological contamination found in this study reflects the inadequate hygienic-sanitary conditions in processing the dairy products, indicating the necessity of abest action, surveillance and control by sanitary authorities.