Growth of halophilic microorganisms and histamine content in dried salt-cured cod (Gadus morhua L.) stored at elevated temperature

- Dried salt-cured cod may occasionally be stored at elevated temperatures.
- Extensive growth of halophilic microorganisms can occur at such conditions.
- Certain halophilic microorganisms are known to produce histamine.
- Very low levels of histamine were detected in spite of extensive growth.

Dried salt-cured fish are highly regarded among consumers in many countries due to the characteristic flavours and storage stability. A temperature-dependent growth of extremely halophilic microorganisms may occur during prolonged storage resulting in red discolouration which limits the shelf life of these products. Halophilic microorganisms require a NaCl concentration of minimum 20 g/100 g product for growth and they are often strongly proteolytic. Histamine formed by microbial decarboxylation of free histidine can be a major problem in seafood safety. The aim of the present study was to examine the growth of halophilic microorganisms in commercial dried salt-cured cod and to determine the histamine content in products with extensive growth of these microorganisms. The results showed that halophilic microorganisms were present in dried salt-cured cod products obtained from the selected commercial producers and they multiplied rapidly at 35 °C. The initial level of the halophilic microorganisms varied among the products from different producers and also within products from the same producer. The levels of histamine remained low even in products with extensive growth of halophilic microorganisms. This shows that consumption of dried salt-cured cod products is not associated with risk of histamine poisoning.