Performance metrics for slaughter and dressing hygiene at Australian beef export establishments

A study was undertaken to examine hygienic control of the slaughter and dressing process for beef cattle at Australian export processing establishments. Samples were collected from two points during the process: immediately after hide removal and at the completion of dressing before the commencement of chilling. Hindquarter and forequarter samples were collected from 24 establishments, half of which (n = 12) used some form of microbial intervention (in addition to trimming). The overall contamination level on carcass sides was low and was reduced between hide removal and entering the chiller. The concentration and prevalence of indicator bacteria were higher on samples from hindquarters than on samples from forequarters. Application of an intervention, such as hot water, in addition to trimming resulted in a greater reduction in the concentration and prevalence of indicator bacteria than trimming alone, although the level of Escherichia coli and coliform bacteria on all samples was too low to allow meaningful comparisons to be made. Salmonellae were isolated from 2.09 and 0.56% of samples after hide removal and before chilling, respectively. Application of an intervention in addition to trimming did not result in a significant reduction (P = 0.4) of Salmonella prevalence on prechill carcasses. Low levels of bacteria were found on carcasses after hide removal. This, combined with small reductions as a result of trimming and sometimes other interventions, resulted in carcasses with very low levels of bacterial contamination. If performance metrics were to be applied to the slaughter and dressing process, a measure of the expected contamination at the end of the process would provide a more unequivocal measure of the process than either contamination on the carcass after hide removal or any reduction achieved as a result of the dressing process.