Enumeration of thermophilic lactic acid bacteria in ripened cheeses manufactured from raw milk

Samples of Pannigiano-Reggiano and Caciocavallo cheeses were withdrawn at different stages of ripening. High counts of lactic acid bacteria were ascertained at 22 and 45 degreesC up to 60 days of ripening on samples of Parmigiano-Reggiano and Caciocavallo cheeses. Thermophilic lactic acid microflora gradually decreased during the ripening of the two examined cheeses whereas mesophilic lactic acid bacteria increased until 60 days. Most of the strains isolated at 45 degreesC during the first hours of cheese ripening were unable to grow at 15 degreesC, whereas the majority of the strains isolated at 45 degreesC at 30 and 60 days of ripening were capable of growth at both temperatures. Hence, it is possible to conclude that lactic acid bacteria isolated at 45 degreesC during ripening of cooked and "pasta filata" cheeses manufactured from raw milk cannot be classified as thermophilic, but instead as mesophilic lactic acid bacteria which are able to grow at 45 degreesC.