Novel technologies for extending the shelf life of drinking milk : Concepts, research trends and current applications

Drinking milk with longer shelf-life is nowadays required to have access to markets of distant countries. Novel technologies for milk processing, alternative to conventional heat-treatments, may provide milk industry with reliable, efficient and clean equipment for drinking milk manufacture. This review addresses the most promising of these technologies, either under experimental examination or already commercially available. In particular, scientific literature documenting the performances of ohmic heating, microwaves, radio frequency, microfiltration, high pressure, pulsed electric field, and ultrasounds is presented. Attention is given to the respective effectiveness in destroying microorganisms, inactivating enzymes, and avoiding damage to milk components, as well as to the consequent microbiological and physicochemical stability of the processed milk during storage. Although most technologies allow to destroy or remove vegetative bacterial cells, so far none proves to represent a comprehensive alternative to conventional heat treatments. The combination of an alternative technology with mild thermal treatments represents, at the moment, the sole realistic approach to produce fresh-like/high quality pasteurized milk.