A law requiring prepacked food to list ingredients and additives came into force yesterday with the end of a three-year grace period. Supermarkets said they had already complied with the Food and Drugs (Composition and Labelling) Regulations by labelling 10,000 products. The Food and Environmental Hygiene Department said it would prosecute offenders. But Consumer Council chief executive Connie Lau Yin-hing told Commercial Radio she was worried food suppliers would abuse the liability-disclaimer provision by affixing warning labels about allergic content without verifying such content and thus restricting consumers' choice.