Identification of psychrotrophic Micrococcaceae spp. isolated from fresh beef stored under carbon dioxide or vacuum.
Seventy-four Gram-positive, catalase-positive coccal strains were isolated from fresh beef stored under carbon dioxide (< 500 ppm O2) or vacuum for up to 15 weeks at 0, 2 or 4 degrees C. Isolates were identified using biochemical tests listed in several published protocols and the API Staph-Ident System. No isolates were identified as Staphylococcus aureus. Twenty-nine isolates were identified as Staphylococcus saprophyticus (five distinct groups), 24 isolates were identified as Staphylococcus gallinarum and 21 isolates were identified as Micrococcus varians. The staphylococcal isolates were coagulase-negative, non-hemolytic and novobiocin resistant. They produced acid from several carbohydrates under aerobic conditions, hydrolysed gelatin but not collagen, showed lipolytic activity and grew in 15% NaCl. The Micrococcus varians isolates also were salt-tolerant, produced acid only from glucose, fructose and galactose (two strains), and were resistant to lysozyme (1600 micrograms/ml). Lactic acid was the major end product of aerobic glucose metabolism. All S. saprophyticus and M. varians isolates tested contained cell wall fatty acids with chain length > or = C20:0.
Venugopal
R J
RJ
Department of Applied Microbiology & Food Science, University of Saskatchewan, Saskatoon, Canada.
Ingham
S C
SC
McCurdy
A R
AR
D000818:Animals; D001431:Bacteriological Techniques; D002245:Carbon Dioxide; D002417:Cattle; D005285:Fermentation; D005511:Food Handling; D008460:Meat / Q000382:microbiology*; D008835:Micrococcaceae / Q000145:classification / Q000302:isolation & purification* / Q000472:pathogenicity; D008837:Micrococcus / Q000302:isolation & purification; D013210:Staphylococcus / Q000302:isolation & purification; D013211:Staphylococcus aureus / Q000302:isolation & purification; D014618:Vacuum
D002245:Carbon Dioxide