Progress in Pasteurization and Sterilization

Abstract

Pasteurization and sterilization are well established methods for preserving foods. The dominating technique is in-container thermal processing where retorts with steam or hot water are used. Modern retorts are microprocessor-controlled, with possibilities to store processing cycles for a range of products. “Real time” process controllers are gradually coming. Modern retorting systems have automated equipment for pre- and post-retort handling of the containers. On-line integrity control for container leakage is under development.

Pasteurization and sterilization can also be done in-flow in indirect heat exchangers and direct heating equipment, using steam or electricity. Much development is taking place in using direct electric resistance (Ohmic) heating or dielectric microwave and high frequency heating of pumpable foods. There is a fair number of industries where microwaves are used for rapidly heating prepared foods to pasteurization temperatures and a few for microwave sterilization. Finally, a number of new non-thermal pasteurization and sterilization methods are being tried out at present; e.g. high pressure technique, high voltage pulses, light discharges.