Watch out for mold in stored grain

Moisture conditions through out the growing season varied by location, but the state saw temperatures in the high 80s and even 90s, causing some concern.

"One of the concerns that I have is the fact that the corn has been sitting relatively dry at high temperatures, but some at 16% to 17% moisture hasn't gone through the dryer and that can cause mold growth, particularly blue-eye mold," says Dirk Maier, Purdue Extension postharvest grain quality expert.

"Blue-eye" mold is the discoloration of a corn kernel caused by the production of blue-green fungal spores. Two groups of fungi usually cause blue eye, Aspergillus glaucus or a species of Penicillium.

The presence of blue-eye mold indicates that something went wrong in the grain storage process, Maier says.

Blue-eye mold can grow at lower moisture contents and may stay in the grain even after it's been cooled. It would be arrested during that period of time, but when temperatures become warm in the spring, the mold can continue to grow and create problems that can result in quality discounts at the time of sale, he says.

"With the weather change that we are experiencing, now is the time to take advantage of this cooler weather and really use aeration to cool down the grain," Maier says. "Hopefully by the end of October, temperatures will be in the mid- to lower-50s and at that point farmers and elevator managers can turn off their fans until the next cold front moves in. Moving a cooling front through a typical grain storage bin takes at least 150 to 200 hours.

"A normal temperature management approach for storing grain is that by mid- to late-November, grain temperatures should be cooled down with aeration into the 40s and then by the end of the year into the low 30s and upper 20s."

During this initial cooldown, Maier advises farmers and elevator managers to look for any type of steam coming from the grain or any odor coming off the grain.

Both are indicators that the grain is not in as good of condition as it should be. It's possible that there is a problem in one bin and not another; it just depends on when it was harvested and what the moisture content is, he says.

"Removing some of the grain from each bin will typically take the peak and center core out where there is a high accumulation of fine materials," Maier says. "This also provides an opportunity to sample the grain and see if you have blue-eye mold damage or other types of grain damage.

"If some bins have better quality grain than other bins, you will want to adjust the marketing schedule according to that and sell, ship or use the lower-quality grain that may not store as well earlier in the marketing year than you do grain that is in really good shape."

Monitoring stored grain regularly is very important, Maier says.

"Typically we recommend to check grain quality every two to three weeks during the colder months and then more frequently in the spring and summer," he says.

Farmers and elevator managers should check corn in storage because temperatures were optimal for mold growth early this storage season, a Purdue University Extension expert says in a university report.