Identities of the Pseudomonas spp. in flora from chilled chicken

Abstract

Nine broilers from each of two different broiler farms were collected at the slaughterhouse. Microbiological samples were collected from broiler chicken carcasses which were stored aerobically at 3+/-0.5 degrees C for 0, 3 or 8 days. By characterizing 40 colonies per broiler it was possible to evaluate the shift in psychrotrophic bacteria on the skin during cold storage. Most of these bacteria belong to the pseudomonads. The Shewan scheme was used in order to distinguish between four groups of pseudomonads. On fresh poultry group II pseudomonads were most abundantly represented, followed by group IV; group I and III strains were present in lower amounts. Non-fluorescing group II pseudomonads always predominated as spoilage became obvious (day 8). By including 36 reference strains, numerical analysis based on the simple matching coefficient was performed on 180 representatively selected strains. This revealed that Pseudomonas species indeed predominated when spoilage was obvious. Non-fluorescing species were identified mainly as P. fragi, but also as other strains belonging to P. fluorescens biovars A, B, C and F, P. lundensis and cluster 7 strains (unidentified). Microorganisms already substantially present on the fresh poultry were found in the highest numbers at the time of spoilage.