Contamination of broiler carcass skin during commercial processing procedures: an electron microscopic study

Scanning and transmission electron microscopy were used in conjunction with normal microbiological cultural techniques to examine some aspects of contamination of broiler carcass skin by bacteria during processing. The autochthonous skin microflora of poultry, before processing, was mainly Micrococcus spp. which were located in accumulations of sebum-like substances on the surface of the stratum corneum. During scalding and plucking, the skin epidermis was removed, and exposed dermal tissue was contaminated by microorganisms from the mechanical plucker and subsequent stages of processing. Major sources of psychrotrophic contamination were the immersion washer and chiller water. Microbial contaminants were found within a fluid film on the skin surface and inside deep skin channels. Skin microtopography and the presence of the liquid film were implicated as major factors controlling contamination during processing.