■ DON (Vomitoxin) in Wheat
Basic Questions and Answers
■ What is DON?
Deoxynivalenol (DON), commonly referred to as vomitoxin, Human food products are restricted to a 1-ppm level
is a mycotoxin that may be produced in wheat and barley established by the FDA. This level is considered safe for
grain infected by Fusarium head blight (FHB) or scab. FHB human consumption. The food industry often sets stan-
may infect grain heads when wet weather occurs during dards that are more restrictive. DON causes feed refusal
the flowering and grain filling stages of plant development. and poor weight gain in some livestock if fed above the
The occurrence of FHB does not automatically mean that advisory levels. FDA advisory levels are as follows:
DON is present, but a high level of scabby kernels in the
harvested grain means DON will likely be present. Levels 1 ppm Finished wheat products, such as flour, bran
of DON do not necessarily correlate with levels of physical and germ, that potentially may be consumed by
damage in grain. humans. The FDA does not set an advisory level
for raw grain intended for milling because normal
manufacturing practices and additional technology
■ What are the critical levels available to millers can substantially reduce DON
of DON for use in food and feed? levels in the finished wheat product. However,
The concentrations of DON in grain are expressed as parts individual millers or food industries may have
per million (ppm). One ppm is equivalent to 1 pound in 1 stricter requirements than 1 ppm.
million pounds, 1 penny in $10,000, 1 minute in two years,
10 ppm Grains and byproducts destined for ruminating
or 1 wheat kernel in 80 pounds of wheat.
beef and feedlot cattle older than 4 months and
The U.S. Food and Drug Administration (FDA) has
for poultry, providing that these ingredients don’t
established DON advisory levels to provide safe food
exceed 50 percent of the diet
and feed. Unlike aflatoxin in corn, DON is not a known
carcinogen. Furthermore, grain with DON would have to 5 ppm Grains and grain byproducts destined for swine,
be ingested in very high amounts to pose a health risk to providing that these ingredients don’t exceed 20
humans, but it can affect flavors in foods and processing percent of the diet
performance.
5 ppm Grains and grain byproducts destined for all other
animals, providing that these ingredients don’t
exceed 40 percent of the diet
Dwight Aakre, Farm Management Specialist
George Flaskerud, Crops Economist/Marketing Specialist ■ How does DON impact wheat grain
Ken Hellevang, Agricultural Engineer - Post Harvest/Structures quality and product performance?
Greg Lardy, Beef Cattle Specialist
FHB infection during very early kernel development can
Marcia McMullen, Plant Pathologist
Joel Ransom, Agronomist reduce yield by decreasing kernel numbers. Slightly later
Brian Sorenson, Crops Quality Specialist infections cause shrunken, chalky white or discolored
Andrew Swenson, Farm and Family Resource Management Specialist scabby kernels, which often are referred to as tombstones.
In cooperation with the N.D. Wheat Commission Kernels infected late in their development by FHB may
show no visible damage, but still have elevated levels of
DON. A Canadian study (Sinha & Savard, 1997, Can. J. of
Plant Path. 19:8-12) of DON in FHB infected wheat kernels
found an average level of 1 to 1.2 ppm in normal appearing
kernels, 2 to 5 ppm in shriveled kernels, 174 ppm in white
North Dakota State University, Fargo, North Dakota 58105 tombstones, and 274 ppm in pink tombstones.
SEPTEMBER 2005