Heat resistance of Listeria monocytogenes

The heat resistance data on Listeria monocytogenes in culture media and foo ds are summarized. Most heat resistance data for foods have been obtained i n dairy, meat, poultry, and egg products. Limited data have been published on seafood, fruits, and vegetables. The methodologies employed have evolved over time; hence data from earlier experiments are not directly comparable to more recent studies. Many factors influence the heat resistance of L. m onocytogenes. Variation exists among different strains in their ability to withstand heat treatment. In addition, heat resistance is influenced by age of the culture, growth conditions, recovery media, and characteristics of foods such as salt content, a,, acidity, and the presence of other inhibito rs. Listeriae are more heat resistant than most other nonspore-forming food borne pathogens, and thus, processing recommendations based on data from ex periments with Salmonella spp. or pathogenic Escherichia coli may not be su fficient to eliminate similar numbers of L. monocytogenes. The data provide d in this review may prove useful for food processors in determining approp riate times and temperatures for producing foods free of vegetative pathoge ns.