The lactic acid microflora of natural whey starters used in Argentina for hard cheese production

Abstract

Abstract A total of 56 samples of natural whey starters, obtained by two sampling plans and employed for Argentinian hard cheese production, were examined. Seasonal changes in technological (pH, acidity, and acidifying and proteolytic activities) and microbiological (lactic acid microflora characteristics) parameters were analyzed. Furthermore, phage resistance and IS 1201 identification were studied among Lactobacillus helveticus isolates. Although technological characteristics of the cultures did not show significant variations, the relative proportion of Lb. helveticus and Lb. delbrueckii subsp. lactis was different between sampling 1 and 2. As a consequence, frequences of fast, intermediate and slow bacterial variants were also variable. On the other hand, lactic acid microflora showed a rather low tolerance to NaCl. Among Lb. helveticus strains, phage resistance was widespread and the presence of IS 1201, a specific insertion sequence for this species, was also demonstrated.