Occurrence of Salmonella spp and Escherichia coli O157: H7 in raw meat marketed in São Paulo city, Brazil, and evaluation of its cold tolerance in ground beef

RESUMO

Among foodborne diseases, salmonellosis has been considered one of the major public health problems in many countries worldwide. Escherichia coli O157H7 has been another important foodborne pathogen due to its increasing incidence as a human disease agent and its association with various kinds of foods, especially those from animal origin. Incidence of Salmonella spp. and E. coli O157H7 in the raw meat (bovine, swine and chicken) marketed in São Paulo - Brazil was determined in 253 samples. Twenty-three samples (9.1%) were positive for Salmonella spp. Among these, 11 different serovars were identified, and S. Enteritidis was found to be the most prevalent. All the tested samples were negative for E. coli O157H7. Salmonella Enteritidis (the predominant serovar) and E. coli O157H7 were also tested for their cold-temperature sensitiveness in ground beef kept under refrigeration (4ºC) for 120 days and under freezing (-18ºC) for up to 90 days. E. coli O157H7 inoculated into ground beef was more sensible to refrigeration and freezing temperatures than S. Enteritidis, but both maintained viability under freezing condition up to 90 days