QS is a symbol of food safety. QS is the abbreviation of "quality and safety" in English. The function of QS mark is to show the quality of products, and it is the quality reputation mark of physical products. Sticking the QS logo on the product packaging represents the express guarantee of the production and processing enterprises to the products they produce.

QS system is a market access system for food quality and safety introduced by AQSIQ in 2002. All food production enterprises entering the system must obtain the food production approval certificate and affix the QS mark on the sales unit before entering the market.

QS mainly includes three contents:

(1) Implement the production license system for food production enterprises.

Issue food production licenses to enterprises that have the necessary production conditions and can ensure food quality and safety, and allow the production of products within the scope of the license; Enterprises that have not obtained a food production license may not produce related foods.

(2) Implement a compulsory inspection system for the food produced by enterprises.

Enterprises are required to fulfill their legal obligations, and food that has not been inspected or failed to pass the inspection shall not be sold out of the factory. For production enterprises that do not have the conditions for self-inspection, entrusted inspection must be carried out.

(3) Implement the quality and safety market access labeling system for foods subject to the food production license system.

The food that has passed the inspection shall be printed with (affixed with) QS mark, and the food that has not been affixed with QS mark shall not be sold out of the factory.