Corn containing less than 20 parts per billion aflatoxin is considered safe by the U.S. Food and Drug Administration for use in all animal feed. Corn exceeding 20 ppb can be fed only for specific age, weight, and production stage. Corn exceeding 300 ppb must be blended with corn containing little or no aflatoxin before feeding is allowed to specific age, weight, and production stage of livestock. Before corn can be blended, the U.S. Food and Drug Administration must be notified and permission obtained from the Missouri Department of Agriculture for this to be allowed.

U.S. Food and Drug Administration guidelines are as follows:

Aflatoxin Level
(parts per billion)
Commodities & Species
20 ppb For corn, peanut products, cottonseed meal and other animal feeds and feed ingredients intended for dairy animals; for animal species or uses not specified below, or when the intended use is not known.
20 ppb For corn, peanut products and other animal feeds and feed ingredients, but excluding cottonseed meal, intended for immature animals.
100 ppb For corn and peanut products intended for breeding beef cattle, breeding swine or mature poultry (e.g. laying hens).
200 ppb For corn and peanut products intended for finishing swine (100 pounds or more).
300 ppb For cottonseed meal intended for beef cattle, swine or poultry (regardless of age or breeding status).
300 ppb For corn and peanut products intended for finishing beef cattle (i.e., feedlot cattle).