IDENTIFICATION OF PSYCHOTROPHIC MICROCOCCACEAE SPP ISOLATED FROM FRESH BEEF STORED UNDER CARBON-DIOXIDE OR VACUUM

Seventy-four Gram-positive, catalase-positive coccal strains were isol ated from fresh beef stored under carbon dioxide (< 500 ppm O2) or vac uum for up to 15 weeks at 0, 2 or 4-degrees-C. Isolates were identifie d using biochemical tests listed in several published protocols and th e API Staph-Ident System. No isolates were identified as Staphylococcu s aureus. Twenty-nine isolates were identified as Staphylococcus sapro phyticus (five distinct groups), 24 isolates were identified as Staphy lococcus gallinarum and 21 isolates were identified as Micrococcus var ians. The staphylococcal isolates were coagulase-negative, non-hemolyt ic and novobiocin resistant. They produced acid from several carbohydr ates under aerobic conditions, hydrolysed gelatin but not collagen, sh owed lipolytic activity and grew in 15% NaCl. The Micrococcus varians isolates also were salt-tolerant, produced acid only from glucose, fru ctose and galactose (two strains), and were resistant to lysozyme (160 0 mug/ml). Lactic acid was the major end product of aerobic glucose me tabolism. All S. saprophyticus and M. varians isolates tested containe d cell wall fatty acids with chain length greater-than-or-equal-to C20 :0.