Vomitoxin in Wheat: How Much is too Much?
Producers who see head scab during their wheat harvest may wonder if it's infected with vomitoxin, and if so, exactly how much is safe. The FDA says the following vomitoxin levels are safe for consumption by:
A chemical analysis will answer your questions. There are a host of commercial labs and quick-test kits for mycotoxin analysis. For more information about the mycotoxin test kits contact your Extension office and ask for Purdue publication BP-47 "Mycotoxins and Mycotoxin Test Kits." Purdue's Plant and Pest Diagnostic Lab also can help.
Woloshuk says moisture control is key. The fungus needs 22- to 25-percent moisture to grow. He says moisture content of stored scabby grain should be below 13 percent to prevent the spread of vomitoxin.
Woloshuk says using a cleaner to remove fines from the wheat before binning and a grain spreader to distribute scabby kernels more evenly will minimize spoilage risks. If a cleaner and spreader are not available, the wheat should be cored as soon after binning as possible. Drying will not reduce scab or vomitoxin levels but it can't hurt. When storing scabby grain, don't mix it with good grain.
If the grain is being dried in-bin with unheated air, the grain moisture at harvest should be below 18 percent. With scabby grain, it may be necessary to increase the rate of air flow to decrease the drying time. This can be achieved by reducing the depth of grain in the drying bin below normal levels. If the harvest moisture is above 20 percent, it will be necessary to use heated air in either bin or column dryers.
For more information, contact your local Extension office and ask for Purdue publication ID-96, "Double Cropping of Winter Wheat and Soybeans In Indiana," and Grain Quality Task Force fact sheet #11, "Drying Wheat to Prevent Spoilage and Sprouting."