Aims and present state of radiation processing of fish and seafood

Acceptability of radurized (pasteurized by ionizing radiation) or radappertized (sterilized by ionizin radiation) fishery products depends on the quality of fish irradiated. Though the organoleptic test is subjective, it allows a correct estimate of the quality. The correlation that exists between the adulteration degree estimated by chemical tests (T.M.A., total volatile bases, total volatile acids) and the organoleptic quality of the product is very variable. Further research is necessary to improve the methods currently used for quality determination. However, it can be assumed that the quality of radurized fish depends on its initial quality, storage time, preirradiation storage temperature and absorbed dose of radiation. Gamma irradiation causes both qualitative and quantitative changes in the microbial flora. Selective reduction in the microbial flora may be favourable to the development of Clostridium botulinum. This microorganism may produce toxins at refrigeration temperatures; radurization cannot eliminate the spores of Clostridium botulinum type E (the most often encountered in fish). Other food infection and food poisoning microorganisms like Salmonella species, Staphylococci and Enterococci survive radurization. Techniques such as irradiation on board, or combining refrigeration and irradiation may increase the storage life