Brussels -- European Union food companies that import illegal genetically modified foods risk legal action by national governments, the European Commission said Tuesday after environmental groups said an illegal and potentially dangerous biotech strain has been found in Chinese food products sold in the U.K., Germany and France.

Greenpeace International and Friends of the Earth Tuesday said their experts found Chinese rice-based products sold in Asian supermarkets in Germany, the U.K. and France contaminated with an experimental strain of genetically engineered rice that's not been approved for human consumption.

The groups called for an immediate ban on Chinese rice.

The European Commission said the groups should submit their samples and findings to national test centers and the E.U.'s central biotechnology laboratory in Italy.

"The presence of traces of unauthorized GMO food in the E.U. is illegal and it is the responsibility of food operators to ensure that they do not place on the market food that doesn't comply with E.U. law. Food operators are clearly not doing enough," E.U. food and consumer protection spokesman Philip Tod said.

The Commission wrote Friday to food operators telling them "that they are not doing enough" to ensure imports are free of illegal biotech strains, Tod said. European governments should punish companies importing illegal crops.

"We would expect member states to take action against any companies not complying with their obligations under E.U. food law."

The food scare is the second in as many weeks and casts doubt over the ability of biotech companies to control their crops. Late last month Europe imposed strict screeing rules on imports of U.S.-farmed long-grain rice following the discovery of an illegal biotech strain in commercial stocks there.

European food safety experts - who have the power to impose import bans - are meeting in Brussels Tuesday and Wednesday. It is unclear whether the issue will be discussed.

Greenpeace warned the strain "poses serious health risks" and called on European governments to "take immediate action to protect consumers." It said the rice -- which is modified to resist insects -- contains a protein that has reportedly induced allergic-like reactions in mice.

"Five positive samples were found containing an illegal GE not approved anywhere in the world. However, this could be the tip of the iceberg with rice products included in everything from baby food to yoghurt," Greenpeace said in the statement.

Countries that grow and produce biotech crops should be required to certify their exports biotech-free, Greenpeace said. Such certification "is reasonable, cost-effective, and necessary to protect Europe's consumers."

Chinese seed companies have been selling the illegal strain to farmers, Greenpeace said.

Last week authorities in the Dutch port of Rotterdam stopped a shipment of U.S. rice thought to be contaminated with the illegal strain. U.S. authorities have declared the U.S. rice strain safe for human consumption.