MICROBACTERIUM THERMOSPHACTUM, SPEC NOV; A NONHEAT RESISTANT BACTERIUM FROM FRESH PORK SAUSAGE

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Abstract
A Gram-positive rod associated with flavor deterioration was isolated repeatedly from fresh pork sausage. The organisms are nonmotile, and vary in length from coccoid forms to long filaments, but are uniformly 0.6 wide. Large bodies occur between coils of the filamentous form of the organism in 48-hr, subcultures from old veal infusion cultures previously stored for 9 months in a refrigerator. The organism grows well at 20[degree] to 22[degree] C but does not grow at -4 or +37[degree] C. It does not form H2S or indol, does not reduce nitrates, does not liquefy gelatin, does not utilize citrate or urea. Acid, but no visible gas is formed from arabinose, glucose, lactose, sucrose, maltose, xylose, cellobiose, dulcitol, mannitol, and starch. CO2 is formed during carbohydrate fermentation. L (+) lactic acid is produced, the Zn salt of which has a specific rotation of [[alpha]]28D= -6.2[degree], indicating about 80% of the acid to have been optically active. The organism is catalase positive and thermolabile. Catalase activity and thermal survivor curves are given. The low heat resistance, type of lactic acid production, habitat and morphology distinguish this species, M. thermosphactum, from the existing species of Microbacterium.