ASSESSMENT FOR GROWTH AND SURVIVAL OF Listeria Monocytogenes IN POWDERED MILK

To assess the growth and survival of Listeria Monocytogenes in spiked powered milk of different water activity at different temperature.Listeria Monocytogenes was added into powdered milk of different water activity at a density of 103 cfu/g,the spiked powered milk stored at the different temperature,the influence of different temperature and different water activity on the growth and survival of Listeria Monocytogenes in the powered milk was analyzed by counting.The temperature influenced the growth and survival of Listeria Monocytogenes in powered milk of different water activity.The Listeria Monocytogenes in powered milk of low water activity could be maintaining growth activity for a long time at low temperature and the number of Listeria Monocytogenes in powered milk of high water activity could increase.However,the Listeria Monocytogenes growth activity decreased very quickly at high temperature and the cell was sublethal,but the growth activity of sublethal Listeria Monocytogenes could recover in the appropriate condition.The growth activity of Listeria Monocytogenes decreases easily at high temperature.If powdered milk was contaminated with Listeria Monocytogenes,the growth of Listeria Monocytogenes will be controlled when being stored at room temperature(25℃).