Caseinolytic Activity of Micrococci Isolated from Cheddar Cheese

Abstract

Micrococci counts of Cheddar cheese, plated throughout ripening, never exceeded 10 X 103 and, after 3.5 months of ripening, few micrococci (less than 10 X 10") grew on the selective tryptone agar medium. Eighteen micrococci were isolated from 5 lots of cheese at various times during ripening. Three of these formed extracellular proteinase which hvdrolyzed preferentially a~-casein. Intracel[ular extracts from all isolates degraded preferentially the r-casein moiety of isoelectric casein. Casein hydrolyzates did not stimulate acid production by a Cheddar cheese Lactobacillus isolate.