Taxonomy of lactic acid bacteria associated with vacuum-packaged processed meat spoilage by multivariate analysis of cellular fatty acids

The taxonomy of lactic acid bacteria from vacuum-packaged processed meats is problematic, and atypical members of the leuconostocs and the Lactobacillus sake/curvatus group are often encountered. In order to resolve this problem the cellular fatty acid (CFA) content of 61 isolates from vacuum-packaged vienna sausages and 18 reference strains was determined by gas chromatography. The relationship between strains was derived by principal component analysis of data. The CFA profiles were highly reproducible. Although no relationships could be derived using only one or two differentiating CFAs, plots of the first two principal components based on only the six most variable CFAs allowed grouping of strains. The two genera (Leuconostoc and Lactobacillus) could not be clearly separated when analysed together, but differentiation of species within each of the genera was achieved when they were analysed independently. Examination of plots for the reference strains confirmed previously established relationships between these strains. From the plot of the Lactobacillus sake/Lactobacillus curuatus component of the study it was found that most atypical Lactobacillus sake/curvatus strains were closely related to the typical Lactobacillus sake isolates and reference strain, while the Lactobacillus curuatus strains formed an independent grouping. A small cluster of atypical strains, however, indicated that this relationship may not be true for all these strains. Among the leuconostocs only isolates of Leuconostoc mesenteroides could be clearly differentiated.