Food quality is an important food manufacturing requirement, because consumers are vulnerable to any form of contamination. Many consumers also need to rely on the standards of manufacture, particularly to know what ingredients are present, due to dietary requirements, which may be associated with religious dietary laws (see kashrut, halal) or medical conditions (e.g., diabetes, or allergies).

In addition to the quality applied to ingredients, there is also significant need to control the environment where food is produced to ensure that it is hygenic and exposed only to appropriate temperatures. Traceability of the source of ingredients and processes used to manufacture food are key techniques, as is the implementation of food labelling standards coupled with best-before dates.

The most common result of poor food quality is foodborne illness, which is most often a result of contamination by bacteria followed by the food's being kept for too long at an elevated temperature favorable for bacterial growth. Under optimal conditions, bacterial numbers can double every 20 minutes or so and, although the bacteria may not themselves be harmful, they may produce potent toxins. Cooking at a temperature greater than 60 °C for an appropriate length of time kills bacteria, and chilling and freezing make bacteria dormant. However, if these processes are carried out too late, the toxins already existing may not be affected.

Ensuring that the food supply is of a consistent and known quality is one of the main goals of agricultural policy; additional goals are to ensure that the food is wholesome, free of pesticides and other contaminants, and attractive. Other objectives of agricultural policy, such as crop intensive cultivation or introduction of genetically modified (GM) crops may not have full consumer support nor be of long-term value. There is a large consumer following for organically grown food that has not been exposed to any form of chemical treatment.