Japanese consumer groups demanded on Friday that the government impose a ban on domestic sales of corn seeds imported from the United States over fears of contamination by the unapproved biotech corn, StarLink . Consumer groups made the request after it emerged that there is a possible risk of StarLink contamination in this year's US corn crop. The consumer groups said in a statement that they had asked the government for mandatory labelling on corn seed or a halt of planting genetically modified seeds on the domestic market.