High-pressure pasteurisation

Claims have been made for the successful high-pressure pasteurisation of fruit juice in containers. The equipment required is expensive and the process is carried out as a batch operation, which tends to be both slow and ineffective. It may, in future, provide a very interesting means of low-temperature pasteurising of fresh juices, thus retaining all the flavour characteristics of the product. 

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Polydera, A.C., Stoforos, N.G., and Taoukis, P.S. 2003. Comparative shelf life study and vitamin C loss kinetics in pasteurised and high pressure processed reconstituted orange juice. J. Food Eng. 60, 21-29. 

In industrial and also in culinary practice, methods based on physical principles are widely used in addition to these chemical methods of food preservation. Of these, it is primarily food preservation by heat treatment (pasteurisation and sterilisation), cold (chilling and freezing), drying (dehydration), irradiation, and more recently by high pressure, which attract the most attention. 

Yen, G.-C. and Lin, H.-T. (1996) Comparison of high pressure treatment and thermal pasteurisation effects on the quality and shelf life of guava puree. International Journal of Food Science and Tedmology, 31, 205-213. 

Additionally, in some applications, where the can is being filled with food products, the coatings and inks must also be sufficiently resistant to withstand pasteurisation at 80°C (beer cans) or, in the case of canned meats and other food products, the coatings need to be retortable (resistant to steam under pressure in an autoclave) because many products are cooked in the can. Temperatures as high as 140°C for over 1 hour may be used, depending upon the size of Ae can and the type of foodstuff being processed. It is not commonly appreciated that foods and beers are heat processed after being filled in their containers rather than before. 

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