Mickael Vallee, a professional fisherman, holds glass eels he fished on March 18, 2015 in Cordemais, western France

Lisbon (AFP) - A European operation has spared revellers a potential food poisoning nightmare before Christmas, seizing 30 tonnes of molluscs illegally fished in polluted waters and arresting 62 suspects, authorities said on Thursday.

Law enforcement in Portugal, France and Spain seized the molluscs and six tonnes of glass eels worth up to 10 million euros ($10.4 million) on the seafood market, Europol said.

The delicacies can fetch up to 25 euros per kilo (2.2 pounds), but poaching gangs exploited Asian workers by paying them just one euro per kilo of molluscs fished in contaminated Portuguese waters.

This made the case the first proven crime in the European Union combining environmental offences and human trafficking for labour exploitation, Europol added in a statement.

The gangs mainly fished Japanese clams, especially popular during the Christmas season on the Iberian Peninsula, and falsified the documentation to present them as fit for consumption.

This could have sparked a public health alarm as the continuous consumption of contaminated molluscs puts people at risk of developing serious illnesses including hepatitis.

Spain-based companies imported the seafood from neighbouring Portugal and sold them without carrying out obligatory sanitary measures to boost their profits, the Spanish Civil Guard added in a statement.

The operation, coordinated by Europol, involved the Civil Guard, French gendarmes and Portugal’s National Republican Guard.