The Principles of Canning for Fishery Products: Selection of Thermal Processing Conditions

The purpose of sterilizing cans of fishery products is to rid the container and the contents of all pathogenic micro-organisms and to prevent. spoilage by non-pathogenic contaminants under normal storage conditions. Selection of processing conditions necessary to fulfill these criteria is based upon experimental studies in which the rate of heat penetration to the slowest heating point (SHP) of the container is measured during simulated retorting cycles.

The data from these trials (or from suitable reference sources) are .used by fish canning technologists to determine the processing temperatures and times necessary to render the canned product commercially sterile. Manufacturers of canned fish (and all low-acid canned foods) can specify their thermal processes in terms of target Fo values, where the Fo value is a measure of thermal processing severity.

Having selected an appropriate Fo value (which may be far in excess of that required to reduce to an acceptably low level, the probability of survival of Clostridium botulinum spores as may be the case when the process is designed to bring about bone softening) the canner then adopts a time and a temperature for the thermal process which will ensure its delivery at the SHP of the container.

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