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Behavior of Enterobacter aerogenes and Hafnia Species During the Manufacture and Ripening of Camembert Cheese
- Rutzinski, J. L., Marth, E. H., Olson, J. L.
- Journal of food protection 1979 v.42 no.10 pp. 790-793
- Camembert cheese, Enterobacter aerogenes, Hafnia, agar, bile, coliform bacteria, manufacturing, most probable number technique, pH, pasteurized milk, ripening, starter cultures, storage time
- Camembert cheese was made from pasteurized milk contaminated with about 10(2)–10(3) cells of Enterobacter aerogenes or Hafnia sp. The coliform bacteria were enumerated with a Most Probable Number procedure and with violet red bile agar. Numbers of viable E. aerogenes decreased rapidly during ripening at 15.5 or 10 C when cheese was made with the commercial lactic starter cultures OD or C-5. No viable E. aerogenes was detected in cheese ripened at 10 C for 3 weeks. Ripening of cheese, made with starter culture OD or C-5, for 1 week at 15.5 C was accompanied by a decrease in numbers of viable Hafnia sp. to 10/g. The number of Hafnia sp. increased markedly during 7 weeks of further ripening at 10 C to yield cheese which contained numbers in excess of 10(7)/g when ripening was almost completed. Growth of Hafnia sp. during the storage period coincided with an increase in pH of the cheese.