가열조건이 listeria monocytogenes의 손상에 미치는 영향

Effects of heat condition on injury of listeria monocytogenes

In this study, Listeria monocytogenes were heat-treated under different conditions and injury of the orgainsim was examined. Also determined was effective method to recover the heat injured cells in enrichment or selective media. Dead cells of L. monocytogenes strain Scott A after heating at 55℃ for 10, 20, and 30 minutes were 0.6, 2.0 and 5.9 log CFU/ml, respectively, and injured cells were 0.4~O.6 log CFU/ml. In buffer pH 5.0, 6.0 and 7.0, dead cells were 1.8, 0.6 and 0.8 log CFU/ml and injured cells were 5.3, 2.9 and 3.2 log CFU/ml, respectively. As the heat injured cells in PBS containing 0.5, 2.5, 5.0 and 6.5% NaCl were respectively 3.8, 4.1, 4.7, and 5.3 log CFU/ml, the effect of NaCl for injury of L. monocytogenes was dose correlation, but dead cells were less than 1.1 log CFU/ml without regared to the concentration of NaCl. Although dead cells and injured cells were respectively less then 1.0 and 2.0 log CFU/ml in beef, chicken meat and milk, the levels of heat injury were not significantly different in kind of foods. When cells resuspended in buffer were held at 43 or 48℃ for 30 minutes before being exposed to 63℃, heat shock allowed the organisms to survive longer than nonheat shocked cells.