The European Food Safety Authority (EFSA) has provided clear guidance on safe storage temperatures for pre-packed fish and other sea-foods noting that storage times and CO2 content in packaging are the two main factors that influence the effect of temperature on histamine formation, the main temperature-dependent hazard.
In its latest guidance, the EFSA has identified combinations of storage times and CO2 content that meet the EU food safety criteria for various storage temperatures.
Histamine poisoning is a common illness caused by fish and other sea-food products and one of the main reasons of its formation in sea-foods is improper storage and refrigeration before it is cooked or processed. EU legislation controls the amount of histamine that should be present in fish.
Some of the fish in which histamine can be found are tuna, sardines, mackerel, and anchovies. Though fishery products containing high levels of histamine do not look or smell bad, but they can cause illness.
The symptoms include tingling or burning of the mouth or throat, rash, headache, diarrhoea and usually start within one hour after eating.
“Cooking, freezing and canning will not destroy this toxin, histamine, after it has formed. The best prevention is to stop it from forming by maintaining the cold chain and keeping fish refrigerated,” explains Ernesto Liebana, Head of EFSA’s Biological Hazards and Contaminants unit.
To carry out the assessment, EFSA scientists used predictive bacterial growth models that assume favourable conditions for histamine formation. These models estimate the rate of microbial growth or provide an indication of whether growth of a particular microorganism will occur under a specified set of conditions.
While EFSA identified histamine formation as the main hazard, the opinion also evaluated Listeria monocytogenes, Clostridium botulinum, and Yersinia enterocolitica.
Fishery products considered in the report are fresh products such as cod fillet; thawed unprocessed products such as sushi; cooked and chilled products from crustaceans and molluscs, such as cooked crab or vacuum-packed crab meat.
The modelling results showed that packaged fresh fishery products can be stored at refrigeration temperatures above 0 °C (e.g. 3–5 °C) and be compliant with the current EU and international rules.
For histamine, the modelling results showed that, for a fishery product with certain characteristics subject to the current temperature requirement, histamine formation would be 100 ppm (lower limit m of the safety criterion in EU Regulation (EC) No 2073/2005) at the end of its shelf-life.
For a retail temperature of 3 °C, 100 ppm would be reached under the following conditions: (1) shelf-life of 6 days and 0 % CO2 in the packaging headspace, (2) shelf-life of 7 days and 20 % CO2 in the packaging headspace or (3) shelf-life of 8 days and 40 % CO2 in the packaging headspace. Similar estimates are provided for the other hazards identified.
You can find the full report here.