Synergistic effect of heat and sodium lactate on the thermal resistance of Yersinia enterocolitica and Listeria monocytogenes in minced beef

The effect of sodium lactate (NaL) (0, 2.4 or 4.8%), in heating and recovery media, on Yersinia enterocolitica and Listeria monocytogenes numbers recovered from minced beef heated at 55 degrees C, was examined, Survivors were enumerated on selective media at pH 5.7/7.4(Y. enterocolitica) or pH 5.7/7.2 (L. monocytogenes). Recover!; of the organisms depended on the pH and NaL levels in the recovery medium. The heat resistance of Y. enterocolitica (P < 0.001) and L, monocytogenes (P < 0.01) decreased as the concentration of NaL in the minced beef increased from 0 to 2.4% or 4.8%. The thermal destruction of pathogens in foods processed using mild temperatures may be enhanced by the addition of 2.4% NaL.