Shellfish in Norway have low concentrations of E. coli and heavy metals, according to the results of a national monitoring program.

The Institute of Marine Research (Havforskingsinstituttet) reported the findings show Norwegian shellfish on the market are largely safe to eat.

Samples from different cities were analyzed throughout 2018 for chemical contaminants and microorganisms. The report shows 86 percent of 195 samples were below the E. coli limit and of 346 samples submitted by industry, 84 percent were lower than the limit value.

In the microbiological part of the monitoring program, 195 samples were collected throughout the year. Of these, 133 were blue mussels, 25 were scallops, 29 were oysters, three were Pacific oyster, one was Ocean quahog, three were Northern Horsemussel, and one was banded carpet shells.

Some high E. coli levels; no Salmonella
Sampling was done by inspectors from the Norwegian Food Safety Authority (Mattilsynet) and sent to the Institute of Marine Research. All samples were analyzed for E. coli and 21 for Salmonella. The number of E. coli was determined by a multiple tube dilution method (MPN) according to the EU’s reference method.

Live bivalve mollusks in class A areas may be collected for direct human consumption, those in class B areas need purification before being sold and bivalves in class C areas can only be placed on the market after relying over a long period.

A total 167 of 195 samples had E. coli at less than 230 in 100 grams of flesh, which is the limit for classing a site as class A. In blue mussels, the highest number of E. coli was 9,200/100 gram sample, and in oysters, the top count was 2,200/100 gram. Salmonella was not detected in any samples.

A total of 346 samples were sent to IMR by industry. Of these, 320 were blue mussels, 13 were European oyster, three were Northern horse mussel, three were Great scallops, and one of each were banded carpet shells and ocean quahog. Five samples of green sea urchin were also submitted.

The concentration of E. coli was less than 230/100 gram in 292 of the samples. A total of 53 blue mussels and one pacific oyster had a concentration above this level. The highest detected number of E. coli in blue mussels was 24,000/100 gram.

Heavy metal results
Samples of mussels taken by the Norwegian Food Safety Authority for analysis of undesirable substances were collected in spring and autumn from 19 localities. Five samples of scallops, eight of European flat oysters, three of horse mussels, and common whelk were collected.

In total, 26 samples of mussels, five of scallops, eight of European flat oysters, three of horse mussels and one of common whelks were analyzed for copper, zinc, arsenic, selenium, silver, cadmium, lead, mercury and inorganic arsenic.

Thirteen samples of mussels, two of scallops, four of flat oysters and two of horse mussels taken in the autumn were tested for TBT and the persistent organic pollutants (POPs) polychlorinated biphenyls (PCB6 and PCB7), dioxins and dioxin-like PCBs, polybrominated flame retardants (polybrominated diphenyl ethers (PBDE)) and polyaromatic hydrocarbons (PAH).

Element concentrations in mussels were within the same range as previous years, and none of the heavy metals cadmium, mercury or lead exceeded the EU’s maximum level. The highest concentration of cadmium in mussels was 0.32 mg/kg wet weight, which is below the maximum level of 1 mg/kg wet weight.

Concentrations of total and inorganic arsenic were within the same range as previous years, as the highest concentration of inorganic arsenic was 0.10 mg/kg wet weight.

Five samples of adductor muscle and gonad of scallops were analyzed for metals and had concentrations at the same low level as previous years. The highest concentration of cadmium was 0.38 mg/kg wet weight, which is below the upper limit of 1 mg/kg wet weight.

One of the eight flat oyster samples had concentrations of cadmium exceeding EU and Norway’s upper limit of 1 mg/kg wet weight. Two of three samples of horse mussels exceeded the maximum level for cadmium of 1 mg/kg wet weight, and one exceeded the maximum level for lead of 1.5 mg/kg wet weight.

Industry submitted 18 samples of mussels and one of scallops for analysis of metals. None of the results exceeded maximum levels.

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