I beleive aflatoxin has a greater chance of being on corn that is grown in drought conditions.
Have seen “deer corn” being sold which is corn not approved for animal feed because of aflatoxin. The fungus is said to cause abortions in cattle, probably in other animals as well.
Aflotoxin is also often found in peanuts and can cause cancer. One reason I don’t eat peanut butter. I do eat almond butter sometimes.