Assessment of the hygienic characteristics of a beef carcass dressing process

Swab samples were obtained from the surfaces of randomly selected beef carcasses passing through a high-speed dressing process. A single sample was obtained from each selected carcass from one of 10 sites. At each of 3 points in the process, 25 samples were obtained from each carcass site. The aerobic bacteria, coliforms, and Escherichia coli recovered from each sample were enumerated. Values for the means and standard deviations of each set of 25 values were calculated on the assumption that each set of values was log-normally distributed. The E. coli data indicated relatively heavy (mean log numbers > 2/100 cm(2)) contamination of carcasses with E. coli during the skinning of posterior sites; redistribution of E. coli, from relatively heavily to relatively lightly (mean log numbers about 0/100 cm(2)) contaminated sites during evisceration operations, and reduction of E. coli numbers at most sites as a result of trimming and washing operations. However, posterior sites remained the most heavily contaminated with E. coli. The findings for coliforms were similar to those for E. coli. In contrast, the total count data indicated heavy (mean log numbers > 3/cm(2)) contamination of anterior (brisket) sites as well as posterior sites and little redistribution of bacteria during evisceration operations. After trimming and washing operations, the mean log total numbers at most sites were about 2/cm(2), but one brisket site remained heavily contaminated. It is suggested that E. coli or coliform data are appropriate for assessing carcass dressing processes for hazard analysis critical control point (HACCP) system purposes, while total count data are inappropriate for that purpose but may be appropriate, in relation to product storage stability, for quality management (QM) system purposes.