Occurrence of Micrococci in Cheddar Cheese Made from Raw and from Pasteurized Milk

Abstract

The numbers and types of micrococci found in cheese made from raw and from pasteurized milk were studied to determine their relationship to development of flavor. Samples were taken during manufacture and ripening and plated on 1% tryptone agar. The lactic acid bacteria grew poorly on this medium. In raw milk cheeses the non-lactic counts ranged from 600,000 to 10,000,000 per g. by the time the cheeses were removed from the press. These counts decreased slowly during ripening. Non-lactic counts on pasteurized milk controls rarely exceeded 10,000 per g. 78% of the isolates from tryptone agar were micrococci; the remainder were coliforms and miscellaneous types. Two groups of micrococci representing 38% of the isolates showed characteristics indicative of possible importance in the. ripening of cheddar cheese. These organisms were identified as Micrococcus freudenreichii.