Biochemical characterization of lactobacilli from dry fermented sausages.

The characterization of 254 strains of lactobacilli isolated from dry spontaneously fermented sausages from 15 different producers at two different stages of ripening time is reported. The species identified were Lactobacillus sake 55%, L. curvatus 26%, L. bavaricus 11% and L. plantarum 8%. The main criteria for the identification of isolates to species level were: production of lactic acid isomers, presence of mDpm acid in cell walls, deamination of arginine and fermentation of mannitol and melibiose. The composition of the populations of lactobacilli were the same for the two stages of ripening. The deamination of arginine was tested in aerobic and anaerobic cultures and in different media by checking the production of ammonia and detecting the production of citrulline. In 94% of strains tested both methods gave identical results. In two L. sake strains arginine catabolism was dependent on culture media; for two other L. sake strains the deamination of arginine only occurred when oxygen was scarce.