Effect of Some Environmental Factors on Psychrophilic Microbacteria

Abstract

S ummary . The growth of three psychrophilic strains of Microbacterium isolated from meat was studied at 10 temperatures between 0° and 35° and at 6 water activity (a w ) levels between 0.99 and 0.94. The temperature and water relations of the three strains were similar. For all strains the rate of growth was fastest at 25° and a w 0.99, and growth did not occur at 35°. Further experiments on one strain showed that under aerobic conditions the range of water activities permitting growth was independent of temperature, but under anaerobic conditions the minimum water activity increased from about 0.94—0.96 as the temperature was reduced from 25° to 0°. Growth was inhibited by low concentrations of undissociated nitrous acid, and inhibition was greater at 0° than at 10° or 25°.