Enumeration of Aermonas for verification of the hygienic adequacy of swinecarcass dressing processes

Populations of Aeromonas spp. and aerobic bacteria from dehairing equipment and from carcasses passing through different processing steps in a swine s laughtering plant were evaluated to identify the hygienic risks of each ope ration. Sponge samples were taken from the scraper flails in dehairing mach ines and the surface of the shackling table at pre- and post-operation time s, with 20 samples from each location being collected at each time. Increas ed post-operation levels of Aeromonas spp. indicated a buildup and possible spread of these bacteria to carcasses. The belly skins of 40 dehaired carc asses were each sampled at five points along the process line which were af ter the shackling, after the final singeing, after the final polishing, aft er the final wash and after chilling. The levels of microbial contaminants on carcasses varied at each processing step. The heaviest contamination of carcasses with Aeromonas (1.88 log CFU/cm(2)) and aerobic bacteria (2.66 lo g CFU/cm(2)) occurred after shackling. Counts were reduced at other steps a s a result of singeing, washing and chilling operations. However, singed ca rcasses were recontaminated with Aeromonas and aerobic bacteria during the polishing operation. Aeromonas hydrophila were the most prominent motile ae romonads (74.1%) recovered at the plant. The findings for Aeromonas spp. we re similar to those for aerobic bacteria (r(2) = 0.9995) which suggested th at Aeromonas spp. are appropriate indicators for assessing carcass dressing processes.