Iowa is facing its third significant flooding situation in five years, which again raises the possibility of stored grain being inundated with floodwater. With only a few exceptions, flood soaked grain is not useable for feed or food. Iowa Secretary of Agriculture Bill Northey reminded farmers in a June 21 news release that grain impacted by flood waters, whether in the field or in a bin, is considered adulterated and cannot be used for feed or food. Flooding affects both the stored grain and the storage structures. The best option is to move the grain before the flood reaches the bin, but stop using underfloor conveyors and legs once the water starts entering the pits.
Grain and Grain Products
Flood damaged grain is adulterated grain because of the potential for many contaminants to enter through the water. This grain should be destroyed, never blended. Contact local public health and sanitation officials for the best disposal process in your area.
Water coming up from tiles and pits is just as suspect because storm and sanitary sewers are usually compromised in floods. Even field tile water may contain high chemical levels and other contaminants.
Corn will stay at 30 percent moisture after the water drains off; soybeans about 25 percent moisture. The moisture won't travel more than a foot above the floodline.
Good grain on top of flooded grain must be removed from the top or side, not down through the damaged grain. The reclaim conveyors and pits under bins are likely to contain flood water as well. Remove all the good grain before doing anything with the bad portion. Do not start aeration fans on flooded bins.
Mold toxins are likely in rewetted grain. Warm wet conditions are ideal for mold growth. Soaked grain will spoil within a day or two at high moisture and summer temperatures.
Moldy grain is a safety hazard. The attached fact sheet prepared by the Iowa Department of Health for the 2010 flooding gives guidance on the hazards and protective equipment to use when working with moldy grain. Assume that flood soaked grain will be moldy by the time the water has receded enough to permit access to bins.
Take care not to track or mix mud or gravel from flooded grounds into good grain during salvage operations. These materials are potentially toxic for the same reasons as the floodwaters.
FDA allows for reconditioning (washing and drying at high temperatures) in cases where the flood water did not remain long and it is known that the water did not contain contaminants. This situation would be very rare, to know that floodwater was clean. In both the 2008 and 2010 situations, the water was determined to be contaminated; expect that to be true in this case as well.