A numerical taxonomic study of the Pseudomonas flora isolated from poultry meat.

Pseudomonas strains were isolated from both fresh and cold-stored broiler skin. Phenotypically-based numerical taxonomic techniques were used to characterize the isolates and 36 reference strains. For this purpose, Biolog GN Microplates, API 20NE and a number of other biochemical tests were used. Jaccard clustering revealed the predominance of four major Pseudomonas groups: Ps. fragi, Ps. lundensis, strains belonging to Ps. fluorescens biovars and an unidentified group of strains displaying a high degree of similarity to Ps. fluorescens biovars. Within Ps. fluorescens, biovar A was best represented. The marked proteolytic character of members of Ps. fluorescens biovars A, B and C, as well as of members of the unidentified cluster, supports their possible role in the origin of organoleptic defects. In the Ps. lundensis cluster, a distinct group of Ps. lundensis-like species was found. Further genotypic studies should be carried out to clarify the taxonomic status of the Ps. lundensis-like strains and that of the unidentified group resembling Ps. fluorescens biovars A and B.

Identities of the Pseudomonas spp. in flora from chilled chicken.

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.