BACTERIOLOGICAL SURVEY OF FRESHLY FORMED CHEDDAR CHEESE

Freshly formed cheese samples (250) produced by 32 provincially inspected cheese plants were analyzed by 7 regional laboratories of the Ontario Ministry of Health. Coliforms were detected in 61 (25.8%) and fecal coliforms confirmed in 46 (19.5%) of the 236 samples tested, with geometric mean counts/g of 133 and 136, respectively. The incidence of coliforms was highest in Cheddar cheeses made from pasteurized milk (29.7%) compared with the incidence of raw milk cheese (22.0%) and cheese made from milk which were subjected to sub-pasteurization heat treatment (28.2%). Conversely, the incidence of fecal coliforms was lowest in pasteurized milk cheese (17.8%), followed by raw milk cheese (22.0%) and highest in heat-treated milk cheeses (25.6%). Staphylococcus aureus above the screening level of 1000/g was not found in any of the 237 samples analyzed. Salmonella spp. were not detected in any of the 250 samples. Producers of Cheddar cheese should have no difficulty in meeting the microbiological standards adopted by the Health Protection Branch, Health and Welfare Canada.