Heat induced inactivation of microorganisms in milk and dairy products

It is well understood that heat treatment of milk, such as pasteurisation, allows its safe consumption in terms of foodborne illness, while failure in adequate heat treatment has resulted in both product recalls and also foodborne disease outbreaks. Aspects of different heat treatments within the dairy industry that affect relevant microorganisms, with an emphasis on bacteria, are discussed in this review. These include a description of D- and Z-values as measures of heat resistance, the factors that affect D-values, such as different dairy matrices, a discussion of some of the mechanisms associated with heat resistance of bacteria important for dairy products, different types of heating effects on microorganisms present in various dairy products, and recommendations for the most appropriate experimental design for understanding how heat affects microorganisms.