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Microbial Spoilage of Fresh Refrigerated Beef Liver
Author(s) -
SHELEF L. A.
Publication year - 1975
Publication title -
journal of applied bacteriology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.889
H-Index - 156
eISSN - 1365-2672
pISSN - 0021-8847
DOI - 10.1111/j.1365-2672.1975.tb00572.x
Subject(s) - food spoilage , food science , organoleptic , bacteria , lactic acid , biology , meat spoilage , population , microbiology and biotechnology , chemistry , medicine , genetics , environmental health
The types and numbers of micro‐organisms involved in the spoilage of refrigerated beef liver were studied together with pH, hydration and organoleptic changes of the material. Fresh liver harboured a mixed population ( c . 1 × 10 5 organisms/g) of Gram positive cocci, chromogens and non‐chromogens, sporeformers, presumptive coliforms and Gram negative rods. When samples were rejected organoleptically, after 7–10 days at 5°, the contamination attained levels of c . 7–8 × 10 7 organisms/g. Spoilage was due to souring; the pH fell from 6·3 (fresh liver) to c . 5·9. Lactic acid bacteria were predominant and Gram negative bacteria did not exceed 1·0 × 10 6 organisms/g. This type of spoilage is explained by the carbohydrate content of c . 5% in liver. The value of pH appears to be a reliable indicator of liver freshness, with a pH of 6·1 indicating incipient spoilage.