Norway shares results of seafood monitoring

Findings from three seafood monitoring programs in Norway have revealed some non-compliances but an overall positive picture.

The Institute of Marine Research analyzed 43 samples of fish and fish products for histamine content in 2024. Samples were collected by the Norwegian Food Safety Authority (Mattilsynet) at retail and processing plants.

In two samples, histamine was detected at 28 and 110 mg/kg, which is above the limit of quantification of 5 mg/kg. The highest level was found in smoked herring and the other positive was in salted herring.

Results indicate that histamine formation is not a widespread problem in fish and the fish products tested in the project.

Ingestion of a high amount of it can lead to histamine poisoning, which causes various symptoms. These can include a rash, itching, vomiting and diarrhea, headache, tremors, a burning sensation in the mouth, a drop in blood pressure, and, in rare cases, loss of consciousness.

Histamine is mostly reported in tuna and mackerel but sardines and herring have also been associated with high levels. Production of histamine is related to the mishandling of food because of storage at incorrect temperatures and could indicate a rupture of the cold chain. Once produced, it cannot be eliminated by normal cooking or freezing temperatures.

Import and shellfish monitoring findings
As part of another project eight samples were tested for histamine, and all values were below the maximum permitted levels.

This project examined 96 seafood samples using different analytical methods and assays for microorganisms and undesirable chemical substances. Results are from the monitoring program for border control on seafood products imported to Norway from countries outside the EU and the European Economic Area in 2024.

Listeria monocytogenes was detected qualitatively in four of 50 samples, and quantitative analysis found the amount to below the detection limit of 10 cfu/g. Positive samples were two trout fillets imported from Peru, one sample of Pangasius fillets from Vietnam, and one of Humboldt squid fins from Chile. As these products were not intended to be consumed without further heat treatment, they were compliant with EU regulations.

Twenty samples were analyzed for potentially human pathogenic Vibrio and four were positive. One sample of Eastern oysters imported from Canada contained Vibrio alginolyticus, another of frozen whiteleg shrimp from Vietnam had Vibrio parahaemolyticus, a sample of frozen whiteleg shrimp also from Vietnam contained Vibrio cholera, and one sample of Giant tiger prawns from India was positive for Vibrioparahaemolyticus and Vibrio cholerae.

Residues of malachite green and leuco malachite green were detected at a concentration of 1.4 μg/kg in a sample of milkfish from the Philippines. Leuco malachite green was also found in a barramundi from Vietnam. 

The Institute of Marine Research also released findings from the national shellfish monitoring program. A total of 187 samples were collected by the Norwegian Food Safety Authority.

In total, 186 samples were examined for E. coli, and 96 percent had a content of E. coli below 230/100-gram which is the limit for classifying a zone to a so-called A-area and allowing harvest for direct consumption. The highest value was above 180,000/100-g in flat oysters. The 33 samples analyzed for Salmonella were all negative.

Another 282 samples were sent to the institute directly by industry. Of these, E. coli was above 230/100-g in 37 samples, 36 of blue mussels and one of sea vases, where the highest value was 3,500/100-g in two samples of blue mussels. 

One sample of flat oysters exceeded maximum levels, with the cadmium concentration above the upper limit of 1 mg/kg wet weight at 1.3 mg/kg wet weight. One sample of horse mussels was above maximum lead and cadmium levels.

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