Quantifying Bacteria on Poultry Carcass Skin

Abstract

THERE are four sampling methods that have been used for determining numbers of bacteria on poultry meat and carcasses, and a number of variations of each method (Fromm, 1959; Kotula, 1966; and Seekins et al., 1958). The four basic methods are: 1) direct contact plating, 2) swab sampling, 3) rinse sampling, and 4) skin tissue removal. Direct contact plating involves placing the surface of a solid bacterial growth medium directly against the carcass skin, then incubating the medium in the petri plate and counting bacterial colonies. A modification of this method utilizes a moist membrane filter to remove bacteria from the carcass skin. The membrane filter is then placed on the surface of a solidified medium for incubation. This method has three serious disadvantages: a) clumps of bacteria removed from the carcass skin are counted as one colony-forming unit; b) even with moderately contaminated carcasses, individual colonies are not distinguishable…