Effects of pH, water activity, nitrite and sorbic acid on the growth rate of Listeria monocytogenes in cooked meat products and raw ham

Abstract

In order to clarify the factors affecting the growth rate of Listeria monocytogenes in meat products, L. monocytogenes was inoculated into various meat products and raw ham, which is served unheated, and its growth rate along with the effects of pH and water activity (aW) on the growth rate were investigated. L. monocytogenes grew in chicken nuggets and cooked pork loin ham during storage for 60 days at 10°C but did not grow in Vienna sausage which contains sorbic acid over the same period. The effect of sorbic acid on growth rate of L. monocytogenes should be investigated in more detail. On the other hand, L. monocytogenes did not grow in raw ham with pH≤6.0 and a W≤0.93 during storage for 60 days at 10°C. These results suggest that the risk of listeriosis in raw ham can be reduced by adjusting pHand aW.