Growth Temperatures of Ropy Slime-Producing Lactic Acid Bacteria

The minimum, optimum, and maximum growth temperatures of ropy slime-producing lactic acid bacteria able to spoil vacuum-packed cooked meat products were determined on MRS-agar with temperature-gradient incubator Gradiplate^R W10. The minimum growth temperatures of slime-producing lactobacilli and Leuconostoc mesenteroides strain D1 were below -1°C and 4°C, respectively. The low minimum growth temperature allows these bacteria to compete with other bacteria in meat processing plants and in meat products causing ropiness problems. The maximum growth temperatures varied between 36.6-39.8°C. The maximum growth temperature of lactobacilli seemed to be an unstable character. Single lactobacilli colonies were able to grow above the actual maximum growth temperature, which is determined as the edge of continuous growth of the bacteria. The significance of this phenomenon needs further study.