Results of a monitoring program have shown seafood imported into Norway in 2019 was generally safe.

A total of 129 samples were examined by different analytical methods and assays for microorganisms and undesirable chemical substances. Microbiological analyses were performed on 94 samples.

The Institute of Marine Research (IMR) did the analytical work while sampling was by the Norwegian Food Safety Authority (Mattilsynet) at Norwegian Border Inspection Posts.

Sampling targeted hazards associated with each product, and took into account import volumes, compositional nature of products, results from previous monitoring, geographical origin of samples, and information in the Rapid alert System for Food and Feed (RASFF) portal.

Listeria and mold and yeast
Listeria monocytogenes was detected at low levels in one sample of tilapia from China. No samples were contaminated with Salmonella or Vibrio, but Enterobacteriaceae was detected in one test of fish cakes imported from China.

In 2018, Listeria monocytogenes was detected at a low level in Pacific cod from Thailand and Norwegian herring re-imported to Norway from Egypt. Vibrio spp. was found in two of 21 samples; one a whole, headless scampi from Vietnam, and the other peeled, headless scampi from India. Strains isolated from the samples were Vibrio cholerae and Vibrio parahaemolyticus.

In 2019, 10 samples were tested for mold and yeast with positives from one swim bladder from Vietnam, and an Atlantic cod from China. One check examined Pacific oysters for E. coli and norovirus and was negative for both.

Two samples were tested for carbon monoxide and no indication for such a treatment was found. Carbon monoxide is used to treat fresh fish such as tuna to retain a fresh, red appearance for a longer period.

Heavy metal findings
Histamine was checked in 26 samples and all results were compliant with maximum levels. The highest value of 44 milligrams per kilogram wet weight was found in samples of Indian mackerel.

The latest report did not provide any data on parasites while in 2018 examination on 40 samples found nematodes in nine of them but as fish were imported frozen, nematodes were dead and not infective.

For 2019, undesirable trace elements arsenic, cadmium, mercury and lead, were measured in 116 samples. For cadmium, two samples for human consumption showed elevated values. One was dry prawn powder, made of Pandalus borealis, imported from Albania, at a concentration of 5.5 mg/kg dry weight and a sample of dried and frozen anchovy, Stolephorus spp., contained 0.26 mg Cd/kg dry weight. However, considering processing factors and uncertainty of the method, the sample was judged to be compliant.

A sample of Obtuse barracuda from Sri Lanka had a mercury concentration of 0.78 mg/kg wet weight. For lead, all measured values were compliant with the maximum limits. For arsenic there is no maximum limit for seafood.

Mercury exposure for pregnant women
Meanwhile, researchers at the Institute of Marine Research in Norway have evaluated mercury and seafood consumption in a study that involved 137 pregnant women.

One group ate Atlantic cod for dinner twice a week, while the other continued their usual diet. The study, published in the journal Environment International, provides information on the benefits and risks of eating seafood.

Mercury is a heavy metal in different forms throughout the environment. The most toxic form methylmercury, can be found in fish and seafood at varying levels. Methylmercury can be transferred from the mother to the fetus during pregnancy and lead to malformations and developmental issues when exposures are too high.

Synnøve Næss, a doctoral student who led the study, said the team only found a very small difference in hair mercury concentrations between the groups.

“The group that ate fish had about 12 percent higher mercury concentrations compared to the group that continued with their regular diet.”

Næss added results suggest cod is an important and safe source of protein and nutrients for pregnant women.

Look at other fish and chemicals
In those who ate cod, none of the pregnant women exceeded the limit for methylmercury. The European Food Safety Authority set a tolerable weekly methylmercury intake of 1.3 micrograms per kilogram of body weight. This is how much mercury people can be exposed to each week during a lifetime without adverse risks to health.

Researchers measured the concentration of mercury in the hair of participants before and after the study, which lasted from gestation week 18 to the last part of pregnancy. Measuring mercury in hair helps estimate methylmercury exposures and concentrations in the body. They analyzed two-centimeter hair samples, which provide an overview of mercury levels in the body over the past two months.

The U.S. Environmental Protection Agency (EPA) limit value for mercury in hair is 1,000 micrograms per kilo. At the end of the study, participants who ate cod had an average value of 554 micrograms per kilo, while the control group had 485 micrograms.

The goal was for participants to eat 400 grams of cod a week, and on average 300 grams were consumed. Scientists hope to expand the randomized controlled trial approach to investigate other fish species and chemical mixtures in future investigations.