China Thursday asked its catering companies to publicize the food additives they use in their flavorings, beverages and condiments, in the latest effort to crack down on illegal additive use and improve food safety.

A circular issued by the State Food and Drug Administration (SFDA) asks that catering firms report information regarding the food additives used in their food to local authorities by the end of May this year.

In addition, the names of these additives should be clearly posted in restaurants for customers to see, the circular said, adding that catering companies should also reply truthfully to any related inquiries raised by consumers.

Chinese authorities recently vowed to intensify efforts to crackdown on the use of illegal additives in the country's restaurants. A few restaurants have reportedly added poppy shells or industrial wax to some of their flavorings.

The SFDA has vowed to make further efforts to conduct sample tests of beverages and flavorings used in Chinese restaurants.

In addition, restaurants have been asked to publicly promise by the end of May that they will not buy or use potentially dangerous products or use any additives that are not clearly labeled by the manufacturer.