Contamination of beef trimmings with Escherichia coli during a carcass breaking process

Log numbers of total aerobic counts, coliforms and Escherichia coli recovered from beef trimmings collected after a carcass breaking process were, respectively, about 1, >3, and > 3 log units greater than the numbers recovered from carcasses entering the breaking process. The numbers of those three types of bacteria recovered from trimmings tended to increase at successive stages of trimmings collection. Aerobes were recovered from pooled water on cleaned equipment at log numbers up to 5 per sample, from steel mesh gloves after cleaning at log numbers up to 8 per glove, and from detritus persisting in equipment after cleaning at log numbers up to 8 per sample. Coliforms were recovered from most mesh gloves and samples. E. coli were recovered from minorities of mesh gloves and samples of detritus, but were not recovered from samples of water. E. coli generally formed < 10% of the coliforms recovered from any glove or sample. However, E. coli were generally predominant in the coliforms recovered from meat. That difference in the coliform populations recovered from trimmings and cleaned equipment appears incompatable with a conclusion that the trimmings are contaminated during carcass breaking from only the bacterial populations that evidently persist in equipment after cleaning. The data, therefore, suggest that carcasses entering the breaking process may be sporadically contaminated at localized sites with large numbers of E. coli which are distributed over the product during the breaking process in addition to the product being contaminated de novo from improperly cleaned equipment. (C) 2000 Elsevier Science Ltd. All rights reserved.