Skip to main content

How to keep fungus at bay in stored grain

Mycotoxins can quickly sour an otherwise good grain crop. Given generally wet conditions across the Prairies this harvest season, the potential for mycotoxins to develop post-harvest is higher than usual.

Of concern, says Cereals Canada, is ochratoxin - also referred to as OTA - a potent strain that forms in high moisture conditions.

According to plant health experts, though, there are several ways farmers can reduce their risk.

Keep grain cool and dry

We are concerned about more grains going into bins wet than is preferable this year.

“OTA is not a disease of field crops,” says Krista Zuzak, chief plant health officer for Alberta Agriculture. “It’s a grain storage issue. We are concerned about more grains going into bins wet than is preferable this year.”

Ideally, she says, farmers should have access to grain drying systems that can both heat and aerate. In scenarios where heated drying is not possible, Zuzak says farmers need to aerate regularly to prevent OTA from gaining a foothold.

This must be done strategically, however.

Because OTA thrives in warm and moist conditions, mixing warm and moist outside air into grain can increase risk. That warm air can also form condensation on cold surfaces, such as interior walls, which subsequently drips to form wet pockets.

If there are dramatic differences in and outside the storage unit, then it might be best to leave fans off.

“Check that your grain bin is properly sealed, and how your vents are installed. Make sure rain isn’t getting in or condensation isn’t forming,” Zuzak says.

Changing marketing, grain handling

Mitchell Japp, a cereal crop specialist and Barb Ziesman, a plant disease specialist, both with the Saskatchewan Ministry of Agriculture, reiterate that fungal growth and accumulation of OTA and other mycotoxins can be limited by keeping grain cool and dry. However, Japp recommends marketing cereals early to limit the amount of time spent in storage – and consequently, the time period in which OTA-producing fungus can grow.

Between this and previous years featuring wet harvest conditions, he says “more producers have looked at having drying capacity on farm.”

Zuzak also says fungal spores can exist on crop residue from the previous year, as well as within soil. Keep equipment clean, she says, to help reduce exposure. Ziesman expresses a similar sentiment, adding efforts should be made to remove as much leftover green material as possible prior to storage. 

Health, economic impacts of OTA

OTA, like other mycotoxins, can negatively impact human and animal health. It is strictly regulated in the European Union and monitored by end users like Health Canada and the United States Food and Drug Administration. Instances of OTA contamination can therefore have significant trade impacts.

“Keeping it out of grain helps us keep our reputation as a producer of high-quality grain,” Zuzak says.

Overall, Japp believes the efforts made by Canadian farmers to mitigate OTA have been working well.

“I think as a result the record that we’ve had has been fairly positive,” he says. 

Bottom line

Preventing OTA from spreading in stored grain is critical to sustaining markets. Experts state farmers may mitigate risks of mycotoxins in cereals if they keep grain cool and dry, market cereals early to limit time in storage and keep equipment clean. 

Article by: Matt McIntosh