In the aftermath of Irene, the hurricane/tropical storm that battered the East Coast in August, the Food and Drug Administration has released updated advice on how growers can judge the safety of their crops when flood waters have come in contact with the edible portions, and when they have not, as well as when to replant flooded fields and how to avoid cross-contamination of food crops after a flood.

The six-page document, known as a “guidance,” issued Tuesday outlines the government’s most current recommendations but does not set regulations. Growers of food crops are responsible for determining the safety of their crops when fields have been flooded. Flood waters can contain sewage, chemicals, heavy metals, pathogens and other contaminants.

The guidance deals with surface crops, such as leafy greens; underground crops, such as potatoes; crops with a hard outer skin, such as watermelon; and products stored in bulk, such as grains, nuts and corn. The FDA said that if the edible portion of a food crop is exposed to flood waters, it is considered adulterated under federal  law and there’s no way to salvage it for sale.

The guidance is effective immediately. FDA will accept public comments on it. For more information, go here.