MICROBIOLOGICAL QUALITY OF CATTLE CARCASS DURING SLAUGHTER AND OCCURRENCE OF E. coli O157: H7 IN BEEF/ Qualidade microbiológica da carcaça bovina durante o processo de abate e a ocorrência de E. coli O157:H7 na ...

Abstract

Escherichia coli O157:H7, an important bacillus strain associated with serious gastroenteritis in humans, is more frequently derived from the consumption of raw or poorly cooked beef. Cattle are important reservoirs suggesting the possibility that feedlot diet management influences the emergence of Shiga-toxigenic strains. This study evaluates the microbiological quality of carcasses and the occurrence of E. coli O157:H7 using the results from general indicator methods (total viable count, coliform rate and E. coli counts) and by an automated PCR method for the detection of E. coli O157:H7. Samples were collected from (industrially processed) meat trimmings and from carcasses of cattle finished on pasture or in feedlots so that sufficient data for the Hazard Analysis and Critical Control Points (HACCP) could be obtained. Samples of rectal swab for experimental detection of E. coli O157:H7 were also collected. One hundred rectal swabs, 100 samples retrieved from warm carcasses and 323 samples of meat trimmings were analyzed. With the exception of one sample of meat trim (0.31%), all the other samples from excreta and carcasses were negative for the O157:H7 E. coli strain. There were no significant differences between the methods used for cattle finishing. Indicator methods results were considered acceptable in 91%, 85% and 93% of tested samples of carcasses respectively for TVC, coliform and E. coli counts. These results agree with statistical data showing the low occurrence of O157:H7 strain.