The U.S. Food and Drug Administration issued guidance to help prevent the inadvertent introduction of allergens or toxins into the United States food and feed supply. 

The explains how the agency will conduct its early safety evaluation of new proteins in new plant varieties, including bioengineered varieties, that are in development for possible use as food for humans or animals.

Under the guidance, titled "Guidance for Industry: Recommendations for the Early Food Safety Evaluation of New Non-Pesticidal Proteins Produced by New Plant Varieties Intended for Food Use," developers would voluntarily provide FDA with information about the food safety of new proteins at a relatively early stage of development of the new crops.

Following a decision to commercialize a particular crop, FDA recommends that each developer participate in the agency’s voluntary premarket consultation procedures. To date, all new biotechnology-developed plant varieties used for food and feed in the United States have completed these consultation procedures before they entered the market.

You can read the full guidance at

FDA news release