Heat inactivation of staphylococcus epidermidis at various water activities

Members of the family Micrococcaceae play an important role in food spoilage and even in food poisoning. In contrast to members of the family Enterobacteriaceae, these bacteria can grow in media with low water activities. Therefore, the heat resistance of Staphylococcus epidermidis, a rather resistant member of the family Micrococcaceae, was studied at water activities between 0.87 and 1.00. The heat inactivation curves were clearly biphasic at all temperatures and water activities tested. Especially at low water activities, the D-values of the tail phase were extremely high (at 0.87 water activity, a D-value at 70 degrees C of 500 s was recorded).