New light on an old process Available to Purchase

In the traditional canning process the food is heated in its can and the heat treatment, typically 120°C for 20 minutes, is sufficient to sterilise both contents and container. This relatively severe heat treatment has practical disadvantages and in recent years an alternative treatment known as UHT (ultra‐high temperature) processing, has been introduced. The foodstuff, usually a liquid, is heated to a higher temperature for a very much shorter time — 140°C for 5 seconds is typical — usually in a continuous operation. The containers are sterilised separately before filling aseptically with the heat‐processed food. Containers for UHT products are made from plastics (chiefly polypropylene), paper board, aluminium foil or from laminates or other combinations of these materials.