Can eating fresh corn on the cob lead to illness?

Potentially, though it isn't likely. Prior to harvest, the concern is corn mold, more precisely aflatoxins, a group of chemicals produced by the molds Aspergillus flavus and Aspergillus parasiticus. The molds appear yellow-green or gray-green, respectively, on corn kernels. Aflatoxins are considered carcinogenic and reach their highest levels during hot, dry summers. In high-risk years, aflatoxin screening is performed at the elevator or where corn is marketed to prevent unacceptable product from entering commerce. The Food and Drug Administration has established an action level of 20 parts bers billion(ppb) for aflatoxins in corn intended for interstate commerce. At this level, the FDA may seize the corn or simply prohibit its sale. Elevators do not accept corn with 20 ppb or more if it is intended for consumption.
 
Because it is fairly high in moisture, corn also may grow mold growth in the home after a period of time. Government health officials recommend that mold simply be trimmed from hard foods such as cheeses. Corn is classified as a soft food. If it begins to mold, toss it. Once it is cooked, corn is subject to bacterial spoilage--and sooner rather than later if leftovers
aren't refrigerated shortly after serving.
 
 
Source(s):
Iowa State University "Alfatoxins in Corn"
Baylor College of Medicine "After Cutting Off Mold, Is the Remaining Food Safe to Eat?"
FDA "How long Can Leftover Foods Be Left Out of the Refrigerator?"