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

The effect of sodium lactate (NaL) (0, 2.4 or 4.8%), in heating and recover y media, on Yersinia enterocolitica and Listeria monocytogenes numbers reco vered 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 Na L levels in the recovery medium. The heat resistance of Y. enterocolitica ( P < 0.001) and L, monocytogenes (P < 0.01) decreased as the concentration o f NaL in the minced beef increased from 0 to 2.4% or 4.8%. The thermal dest ruction of pathogens in foods processed using mild temperatures may be enha nced by the addition of 2.4% NaL.