Identification of lactic acid bacteria isolated from Roncal and Idiazábal cheeses

Abstract

The lactic flora of two ewe's-milk cheeses regulated by Appellations of Origin, Roncal and Idiazábal cheeses, manufactured in the autonomous region of Navarre (Spain), was identified and compared. 263,494, and 464 isolates of lactococci, lactobacilli, and leuconostocs, respectively, were isolated throughout ripening from both cheeses and presumably identified using morphological, phenotypical and biochemical methods. The distribution of lactococci species was not significantly different in the two cheeses, Lactococcus lactis subsp lactis being the main species from 10 days of ripening. Lactobacillus casei and Lactobacillus plantarum were the major lactobacilli species in both cheeses. In Roncal cheese L casei accounted for 53% of the isolates and L plantarum for 30%, whereas in Idiazábal cheese the frequency of L casei (39%) was slightly lower than the frequency of L plantarum (44%). Leuconostoc mesenteroides subsp mesenteroides and Leuconostoc mesenteroides subsp dextranicum were the predominant leuconostoc species in both cheeses, but the ratios of the two subspecies were approximately 3:1 in the Roncal cheese and closer to 1:1 in the Idiazábal cheese. The experimental results of this work are considered to be a first step to prepare indigenous starters including representative bacteria isolated from each type of cheese.