Atypical Lactobacilli from Vacuum-Packaged Meats: Comparison by DNA Hybridization, Cell Composition and Biochemical Tests with a Description of Lactobacillus carnis sp. nov.

Abstract

Summary Twenty strains of atypical lactobacilli isolated from vacuum-packaged meats in the UK, South Africa and Australia have been compared. Several characteristics were common to all the strains including heterofermentative metabolism, production of most of the lactate as the L( + ) isomer, a meso -diaminopimelic acid ( m — Dpm) type of peptidoglycan and low mol % G+C in the DNA (33–36%). Two groups were, however, distinguishable on the basis of sugar fermentation patterns and the presence/absence of lactobacillic acid in the cellular fatty acids. Deoxyribonucleic acid hybridization revealed that these groups represented two closely related species one of which was identified with Lactobacillus divergens . The other group was considered to represent a new species for which the name Lactobacillus carnis is proposed. Lactobacillus carnis produces only small amounts of gas from glucose and low molar ratios of acetate plus ethanol to lactate suggesting that its metabolism differs from that of typical heterofermentative lactobacilli. Another unusual feature in this species is the absence of lactobacillic acid in the cellular lipids. Both L. carnis and L. divergens appear important components of the microflora of vacuum-packaged meats.