Since 1958, FDA and USDA have continued to monitor all prior sanctioned and GRAS substances in light of new scientific information. If new evidence suggests that a GRAS or prior sanctioned substance may be unsafe, federal authorities can prohibit its use or require further studies to determine its safety. In 1960, Congress passed similar legislation governing color additives. In contrast to food additives, colors in use before the legislation were allowed continues use only if they underwent further testing to confirm their safety. Both the Food Additives and Color Additives Amendments include a provision which prohibits the approval of an additive if it is found to cause cancer in humans or animals.
Manufacturers use only the amount of an additive necessary to achieve the desired effect.
To market a new food or color additive, a manufacturer must first petition FDA for its approval. Approximately 100 new food and color additives petitions are submitted to FDA annually. Most of these petitions are for indirect additives such as packaging materials. A food or color additive petition must provide convincing evidence that the proposed additive performs as it is intended. Animal studies using large doses of the additive for long periods are often necessary to show that the substance would not cause harmful effects at expected levels of human consumption.