Fish Microbiology and Quality Assurance (2+2)

Unit 8 - Spoilage of fresh and processed fish and fishery products

8.2.4. Microbiology and spoilage of canned fishery products
Canned seafoods are expected to be commercially sterile and free from spoilage and potentially pathogenic microorganisms. The bacteriological hazards of canned food mainly results from improper or inadequate processing or leakage of cans. The inadequate heat processing causes survival and growth of heat resistant clostridial spores responsible for botulism. The mesophilic spoilage organisms entering the cans through leakage caused due to improper seaming of cans grow during storage eventually resulting in spoilage of canned product.

The semi-processed canned seafood products are often subjected to bacteriological problems. The stability and safety of these products depend on the factors such as combination of preservatives used and pasteurization process applied. In most pickled products that depend on salt (eg. anchovies) or a low pH (eg. mussel) for stability, the heat process given destroys both hazardous and spoilage microorganisms. Yeast like Pichia fermentans often cause illness after growing in semi-processed canned seafood.

In some smoked products which are canned using minimal heat treatment, the storage stability is attributed to presence of salt, smoke constituents and a low water activity. Thus, production of safe final product can be achieved only by having good control over processing parameters.