Different Lactobacillus helveticus strain populations dominate during Grana Padano cheesemaking

Sixty-two strains of Lactobacillus helveticus isolated from whey starter cu ltures for Grana Padano cheese and from the cheese curd after moulding were grouped by PCR fingerprinting and SDS-PA GE fingerprinting of cell wall pr oteins. Strain clustering allowed discrimination of five groups of L. helve ticus strains, distributed differently between the whey starter and the che ese. in particular, two clearly distinguished biotypes respectively dominat ed the L. helveticus populations of the whey starter and the cheese curd af ter moulding. These two groups of strains also showed a peculiar cell wall protein profile, thus strengthening differences between biotypes alternativ ely dominating in whey starter and cheese curd. This study showed that the community of L. helveticus dominating in Grana cheese is composed of differ ent biotypes. Cheese technology parameters may play a major role in selecti ng dominant strains. (C) 1999 Academic Press.