CHANGES IN THE MICROFLORA OF IDIAZABAL CHEESE WITH THE ADDITION OF COMMERCIAL LACTIC STARTERS

The industrial manufacture and ripening of three batches of Idiazabal cheese made from raw ewe's milk during the winter lactation period wer e studied. Counts of aerobic mesophiles and psychrotrophs in the chees es made using starters were approximately 1 log unit lower, and counts of enterococci were approximately 2 log units lower. Furthermore, ent erobacteriaceae and coliforms were no longer detectable in the cheeses after 30 d of ripening, while in the cheeses made without starter, co unts of these two microbial groups were still of the order of 10(2) cf u/g after 60 d. Batches with added starter exhibited higher levels of lactic acid bacteria, especially during pressing, though no difference s were observed during ripening. Differences in the levels of micrococ caceae, moulds, and yeasts between the three batches were slight. The pH of the starter-containing batches was lower, particularly at the en d of pressing. During cheese ripening differences in pH were smaller. The quality of the cheeses from the three batches was that required by the Appellation of Origin Idiazabal. Flavours of all cheeses were typ ical of matured ewe's milk cheese.