Bacterial Populations of Different Sample Types from Carcasses in the Dirty Area of a South African Poultry Abattoir

Abstract

Bacterial populations associated with three different sample types from carcasses in the dirty area of a South African poultry abattoir were compared. The three sample types from carcasses before and after scalding included neck skin only, feathers only, and a neck skin and feather combination. The neck skin of carcasses after defeathering was also sampled. Aerobic plate counts, Enterobacteriaceae counts, and Pseudomonas spp. counts were performed on all sample types, as well as on water, air, and equipment samples from the same area. The prevalence of potential pathogens was also investigated. Neck skins sampled before and after scalding consistently exhibited the lowest counts for all bacterial types, and feathers the highest. In most cases, the bacterial numbers of the neck skin samples from pre- and postscalded carcasses were significantly lower (P < 0.05) than those of feather samples and neck skin and feather combination samples. Scalding of carcasses resulted in a consistent decrease of bacterial populations, reflected by all three sample types. Neck skins sampled after defeathering, however, exhibited increased bacterial numbers compared to neck skins sampled postscalding, implicating the rubber fingers of the defeathering machine as contamination sources. These equipment surfaces exhibited aerobic plate counts as high as 7.7 log CFU/cm2. Potential pathogens were isolated from product as well as selected environmental samples. The prevalence of the potential pathogens was found to vary depending on the sample type.