Contamination of Beef Chucks with Escherichia coli during Carcass Breaking

Abstract

Samples were obtained by swabbing the whole of the chuck portion on each of the first 500 sides that entered a beef carcass breaking process and the whole of the outer surface of each of the chuck primal cuts that were prepared from those portions. Swabs obtained from groups of 10 sides or cuts that entered or emerged from the process consecutively were combined, and the coliforms and Escherichia coli recovered from each group were enumerated. Coliforms and E. coli were recovered only sporadically from groups of sides at log total numbers of 4.0 and 3.5 log CFU/500 sides, respectively. Coliforms were recovered from three and E. coli from none of the first six groups of cuts. Coliforms and E. coli were recovered from all subsequent groups of cuts, initially at log numbers mostly <3 log CFU/10 cuts, but ultimately at log numbers mostly >3 log CFU/10 cuts. The log total numbers of coliforms and E. coli recovered from cuts were >6.0 and 5.5 log CFU/500 cuts, respectively. After the breaking of about 600 sides, samples were obtained by swabbing a table onto which the part of the side that included the chuck portion was deposited after it was cut from the hanging side, and the belt that was used for conveying chucks. The numbers of coliforms and E. coli recovered from the table and conveyor belt were comparable with the numbers recovered from sides and cuts, respectively. Those findings show that most of the coliforms and E. coli recovered from the cuts were not present on carcass sides but that they originated largely from the cut conveying equipment.

Risk Factors and Control Measures for Bacterial Contamination in the Bovine Meat Chain: A Review on Salmonella and Pathogenic E.coli

“…In a study conducted in an Irish beef abattoir, McEvoy et al (2004) reported increases of 2.3 and 2.1 logcfu/cm 2 respectively for total viable bacteria and Enterobacteriaceae counts on the inside round of carcasses during the cutting/boning operations. Similar increases were also reported in E. coli numbers during the boning of beef carcasses (Gill, McGinnis, & Bryant, 2001). Increases in bacterial/pathogen numbers following the cutting and boning operations could be associated to cross-contaminations.…”

“…Various origins of microbial contamination during cutting/boning were reported in literature. These include carcasses or meat pieces to be processed (McEvoy et al, 2004); meat cutting/boning equipments such as knives, meat conveyors or cutting boards (Gill, Badoni, & McGinnis, 1999;Gill et al, 2001;Jiménez et al, 2009) and soiled surfaces or operators (Sheridan, Lynch, & Harrington, 1992). One of the measures to prevent cross contaminations resulting from contaminated carcasses or meat pieces would be to identify the most contaminated raw materials and to process them separately preferably at the end of the production (Koohmaraie et al, 2012).…”

Developments in sampling and test methods for pathogens in fresh meat

“…This suggests that at plants with well controlled carcass dressing processes, dressed carcasses heavily contaminated with O157 VTEC must be very rare. Moreover, most of the E. coli found on beef at large North American plants are deposited during the processes for fabricating chilled carcasses to cuts and trimmings (Gill et al ., 2001 ;Youssef et al ., 2013 ).…”

Sources of microbial contamination at slaughtering plants

“…Contamination of meat with bacteria from persistent detritus in equipment may be particularly hazardous because, if a pathogenic organism becomes established in the flora, the pathogen may, over lengthy periods, be spread to all product that encounters the contaminated equipment. The risks to consumer health from such contamination in carcass breaking equipment might greatly exceed those from the few pathogens that might survive on effectively decontaminated carcasses from well-controlled dressing processes (Gill et al, 2001).…”