An evaluation of the microbial contamination of carcasses at a local red meat type C abattoir

Abstract

The hygiene practices at a local abattoir were monitored. The main microbial spoilage organisms associated with red meat carcasses were enumerated and characterized from ten bovine carcasses. Instead of evaluating the final product only, samples were taken at regular positions (four) along the carcass processing/dressing line from just after skin removal (flaying) until after a chilling period of between eighteen and twenty four hours. Total aerobic plate counts, Gram-negative counts and lactic acid bacterial counts were determined. The highest microbial numbers were consistently obtained from the total aerobic plate counts (approximately 3 log10 numbers per cm2) followed by the Gram negative counts (approximately 2 log10 numbers per cm2 ) and there were no growths observed on the lactic acid bacteria agar. Characterization of the 104 predominant bacterial isolates from total aerobic plate counts of the carcasses indicated the presence of Pseudomonas spp. (25%), Aeromonas spp (13%), Acinetobacter and Micrococcaceae (10% each) and fewer amounts of species of Moraxella(8%) , Alteromonas (5%) , Brochothrix and Corynebacterium (4% each), Enterobacteriaceae and Staphylococcus (3% each). The microflora from the Gram-negative counts of the carcasses was also dominated by the Pseudomonas spp. (50%), Enterobacteriaceae (15%), Aeromonas spp. (10%) the Moraxella group (5%) and non-reculturable (20%). The possible effects of the carcass dressing procedures and the chilling process on the bacterial counts were determined. Despite the apparent observable trends where the bacterial numbers seemed to decrease after the chilling process they were of no statistical significance.