Genotypic analysis of Escherichia coli recovered from product and equipment at a beef-packing plant

Abstract

Aims: To identify sources of Escherichia coli on beef by characterizing strains of the organism on animals, equipment and product at beef-packing plant. Methods and Results: Generic E. coli were recovered from hides, carcasses, beef trimmings, conveyers and ground beef during the summer of 2001 (750 isolates) and winter of 2002 (500 isolates). The isolates were characterized by Random Amplification of Polymorphic DNA (RAPD). The numbers of E. coli recovered from dressed carcasses were less than the numbers recovered from hides. The numbers recovered from chilled carcasses were too few for meaningful analysis of the strains present on them but the numbers recovered from trimmings and ground beef were larger. The RAPD patterns showed that the majority of isolates from hides, carcasses, beef trimmings, conveyers and ground beef were of similar RAPD types, but a few unique RAPD types were recovered from only one of those sources. The E. coli populations present on the hides of incoming animals and in the beef-processing environment were highly diverse. Randomly selected E. coli isolates from each of the five sources were further characterized by pulsed-field gel electrophoresis (PFGE). Most genotypes of E. coli defined by PFGE corresponded to the E. coli types defined by RAPD. Conclusions: The hides of the incoming animals appeared to be only one of the sources of the E. coli on trimmings and in ground beef, as additional sources were apparently present in equipment used for carcass breaking. Significance and Impact of the Study: This study indicates that hazardous microbiological contamination of meat may occur after the dressing of carcasses at commercial beef-packing plants, which suggests that attention should be given to the control of the contamination of meat during carcass breaking as well as during the dressing of carcasses.

Isolation of Shiga toxigenic Escherichia coli from butcheries in Taquaritinga city, State of São Paulo, Brazil

“…This is a matter of concern because unsatisfactory cleaning of meat grinders have been proven to be a source of contamination during processing (1,8). Warriner et al (26) demonstrated that the same clone of E. coli was isolated from a pork carcass and from the equipment used during the carcass processing.…”

“…Transfer of fecal material to carcasses at slaughter leads to potential contamination of raw meat (6), as also does cross-contamination of meat and processing equipment (1).…”

Phenotypic characterization and genomic DNA polymorphisms of Escherichia coli strains isolated as the sole micro-organism from vaginal infections

“…The primers used were 2H (59-AAGCTTCGACTGT-39) and 3H (59-AAGCTTGA-TTGCCC-3), which were randomly selected among four arbitrary primers. Amplification was done in a DNA Engine (Bio-Rad) thermal cycler programmed to one cycle of 5 min at 94 uC, 10 cycles of 1 min at 94 uC, 1 min at 36 uC, and 2 min at 72 uC followed by 20 cycles of 1 min at 94 uC, 1 min at 50 uC and 2 min at 72 uC to allow the completion of DNA extension (Aslam et al, 2004). A negative control, consisting of the same mixture but using water instead of DNA, was included in each run.…”

Assessment of a handheld fluorescence imaging device as an aid for detection of food residues on processing surfaces

“…Contamination can occur during the slaughtering, dressing, chilling, or cutting stages of processing (Dourou et al, 2011;Koutsoumanis & Sofos, 2004). Many reports demonstrate the potential for cross contamination with E. coli O157:H7 via surfaces of equipment used for beef processing (Aslam, Greer, Nattress, Gill, & McMullen, 2004;Gill & McGinnis, 2000;Gun, Yilmaz, Turker, Tanlasi, & Yilmaz, 2003).…”