Post harvest DON reduction strategies for Canadian western spring wheat, durum and barley

Project Description

The overall objective of this project is to determine the most practical, cost effective methods to reduce deoxynivalenol (DON) levels in Fusarium-infected wheat and barley, with a focus on on-farm applications thereby increasing the value, safety and marketing opportunities for these important crops.

It is difficult to determine the exact cost of Fusarium damage to producers in Saskatchewan and across the prairies and estimates vary widely but in 2014 and again in 2016 the lost revenue and additional transportation, handling and storage costs are likely in the 100’s of millions of dollars on an annual basis. On an individual farm basis, the impact of Fusarium damage can be even more significant. The disease tends to be regional and sporadic in nature due to the impact of growing conditions on the disease. As a result, individual producers can experience significant losses as the majority of their wheat and durum can be downgraded either reducing the grade or in extreme cases making the product virtually worthless. Fortunately, significant investments are being made towards developing new more resistant varieties and producers are investing in extensive fungicide treatments but these alone will not solve the issue and options to deal with infected grain post-harvest is also required. This research will provide those options to producers and allow them to recover significant value from their crop.

Thus, the main objective is to develop and examine strategies for on-farm to reduce the Mycotoxin (DON) in barley and wheat post harvest; and to examine strategies to reduce the mycotoxin (DON) in barley post harvest during seed cleaning. The proposed research will study three DON (vomitoxin) reduction strategies namely physical processes (scouring), oxidation of the DON, and seed sorting to remove individual infected kernels.

Research Results

Deoxynivalenol (DON) is the major secondary metabolite produced by Fusarium graminearum. F. graminearum can infect cereals such as: wheat, durum, barley, rye and corn. This toxin can make the grain unmarketable for producers. This study examined methods to recover high quality (low DON) wheat and barley from infected seed lots.

Seed sorting by BoMill (Near Infrared Transmittance single seed sorting), air fractionating grain cleaning, the combination of the two and oxidation of the mycotoxin through introduction of Ozone gas produced by an ozone generator into the air stream of an aeration bin during grain drying immediately following harvest. The BoMill technology effectively sorted both wheat and barley into high and low DON fractions resulting in recovery of significant quantities of low DON wheat especially when using the Fusarium calibration combined with the appropriate vitreous kernel setting and precleaning. Air fractionation effectively separated infected wheat and barley based on relative grain density but the air speed settings had a significant impact. The combination of air fractionation followed by sorting of mid DON fractions on the BoMill was the most effective method of recovering high quality wheat and barley from material that otherwise had few marketing opportunities. Abrasion of grain followed by air fractionation failed to reduce DON levels. Ozone treatment during drying by aeration significantly reduced DON concentration (up to a 50% reduction) and would be effective when grain is only marginally too high to market but in more extreme cases the combination of air fractionation and BoMill sorting are recommended.

Key findings include:

• DON levels can be reduced in fusarium infected wheat and barley by adding ozone gas to the air inlet during grain drying and aeration.
• Fusarium infected wheat and barley containing high levels of DON can be effectively detoxified and sorted into low DON factions using simple air fractionating grain cleaner or a BoMill NIRS grain sorter
• A combination of grain cleaning followed by BoMill sorting was the most effective method of recovering low DON grain.
• Abrasion of grain followed by air classification did no reduce DON levels, however, grinding with a hammer mill prior to incorporation into the diet did.