Microbial succession during ripening of Naples-type salami, a southern Italian fermented sausage

Studies were carried out on the microbiological and physico-chemical change s which occurred during the ripening of five batches of Naples-type salami, manufactured without starter cultures. Salami were sampled internally and externally, and the following microbial groups were studied: lactic acid ba cteria, Micrococcaceae and yeasts. The results obtained indicated that lact obacilli constituted the predominant flora, both on the surface and in the interior of the pieces throughout the ripening period. Micrococcaceae and y easts were also found in considerable number in both locations. Characteris ation of 191 lactic isolates indicated that the salami microflora was domin ated by homofermentative lactobacilli; approximately 63% of them could be i dentified as Lactobacillus sake; 40% showing the traits of a racemase negat ive variant of this species, once referred to Lactobacillus bavaricus. Yeas t population mainly comprised Debaryomyces strains. All the colonies grown on mannitol salt and Kranep agar were catalase-positive cocci; novobiocin-r esistant staphylococci were the only Micrococcaceae found. The API Staph id entification system did not prove to be reliable: 82% of the isolates remai ned unidentified. To achieve improved characterisation, cluster analysis wa s subsequently performed on this group, corroborating the existence of a fa irly homogeneous group representing an intermediate variety between Staphyl ococcus xylosus and Staphylococcus saprophyticus that was isolated during t he whole ripening process. (C) 2000 Published by Elsevier Science Ltd.