The effects of buying source (terminal market, buying station, outdoor farm, and indoor farm), feed withdrawal before slaughter (0, 2, 4, and 6 h), and the incidence of punctured gastrointestinal (GI) tracts during evisceration on the numbers of pathogenic and spoilage bacteria on pork carcasses were determined. Of the 932 samples tested, a 0% incidence of the pathogens Salmonella spp., Listeria monocytogenes , Campylobacter spp., Clostridium perfringens , and Yersinia enterocolitica was found.A significant (P < 0.05) location effect was found, with the belly-sternum region having higher total plate counts than the head, pelvic cavity, and diaphragm regions of the carcass. A significant (P < 0.05) buying-source effect indicated that pigs from buying stations had higher lactic acid bacteria counts than pigs from outdoor and indoor farms. A buying source by fasting time interaction (P < 0.05) was noted for GI tract weights, with the indoor farm pigs having the highest incidence of ruptured GI tracts. The removal of feed prior to slaughter resulted in lighter GI tract weights and a lowered incidence of vicera rupture resulting in a lowered risk of pathogen contamination of carcasses. The extent of punctured GI tracts during evisceration was influenced by fasting time and buying source and may be useful in a HACCP system for the pork-processing industry.
Keywords: Microorganisms; feed withdrawal; pork carcasses.