All the prepackaged food should be labeled about allergens it contains from July 10, an official from Hong Kong food safety department said on Saturday.

Center for Food Safety Community Medicine Consultant Ho Yuk-yin said in a radio program that the food trade should provide correct prepackaged food labels and check all aspects of their operations to avoid introducing unidentified allergens.

The 36-month grace period of the Food and Drugs (Composition and Labeling) (Amendment) Regulation will expire on July 9.

The new law requires the declaration on prepackaged food labels the presence of the eight most common allergy causing substances, including cereals containing gluten, crustaceans and crustacean products, eggs and egg products, fish and fish products, milk and milk products (including lactose), tree nuts and nut products, sulfite, and peanuts, soybeans and their products.

These allergens account for more than 90 percent of all food allergic reactions, Ho said.

Noting allergens may come from raw materials or come from cross-contamination during production, Ho urged the food trade to take preventive measures, such as thorough cleaning of production lines, to control unidentified allergens or amend labels to indicate the possible presence of allergens.

Ho said different laboratory analysis methods will be adopted before taking any prosecution action. The maximum penalty for violating the regulation in Hong Kong is a fine of 50,000 Hong Kong dollars (about 6,402 U.S. dollars) and six months' jail.