I did something I rarely do this past July–I bought shucked sweet corn. The reason I did this is because I got a dozen ears of un-shucked corn and one ear had some mold on the end. I decided I didn’t want to take a chance of getting moldy ears again. I had to see what I was getting. The question is, how dangerous is corn mold? Well, it depends on the mold.

Mold spores are always on the look-out for a nice place to grow. Mold can travel down the corn silk and attack corn during fertilization, it can enter through cracks in the kernel, or it can grow on the forage products (leaves and such fed to animals), Mold floats about looking for food and moisture, growing where it lands if these are present. July through fall is a prime time for mold to spread and grow.

Corn mold is a tricky thing. Some types are considered a delicacy. Some can cause allergies, and a lot of them generate toxins called mycotoxins.

Mycotoxins are poisons produced by mold that grows on grains and nuts. They cause everything from cancer to kidney problems, to digestive upset, miscarriages and stillbirths, to hallucinations. Moldy rye has been connected to the Salem witch trials and in some cases, plagues of dancing called St. Vitus Dance.

Mycotoxins infect 25% of world’s crops including coffee and beer and make them unfit for consumption. Thank goodness they are regulated as part of our food safety regulations. Detecting them is tricky. A black light can be used to see if they are present but it isn’t definitive proof of them. Lots of things glow under a black light and are not mycotoxins. It takes a time consuming test to prove they are present. You can read much more here.

There are all sorts of corn rots and mold and here are some examples. All of these types of rotting corn should not be fed to animals.

More photos here.

And here,

Particularly dangerous and damaging is Aflatoxin produced by the pervasive Aspergillus mold. It can infect nearly any grain product and was first noted in 1961 when it killed over 100,000 turkeys in England after it infected their peanut-based food. Aflatoxin in dog food recently sickened many pets.

Aflatoxin grows on stressed corn, particularly corn exposed to drought and heat. It is likely to be worst in years with a hot (over 91 degrees F or 30 C), dry June because corn produces its silks in June and the mold travels down the silks and gets in the corn. It can also infect grain bins if they are not kept clean and dry. Once in the feed corn, the aflatoxin can’t easily be removed. It can get in the milk of dairy cows fed the moldy grain. Elevated carbon dioxide levels as found with climate change spur its growth and this is another reason scientists worry about our hotter weather.

Looking back, I don’t think my corn had aflatoxin. On the other hand, I’m glad I didn’t eat it. This is one of the many reasons I support robust food safety regulations and don’t eat moldy ears.