Canada resets mildew grading standards on milling wheat

Mildew damage on individual kernels of CWRS wheat. (

Canada’s visual grading standards for mildew in Prairie milling wheat have been relaxed to reflect what’s now known about the actual quality of affected wheat.

The Canadian Grain Commission on Friday announced new mildew guidelines, “effective immediately,” for western Canadian milling wheat classes, to allow for an “increased presence” of mildew in visual guides and standards.

The new guidelines won’t have any impact on the quality of products made from Canadian wheat, but will help to “minimize the financial impact” on producers and the grain industry, the commission said.

The commission said the changes stem from its finding in September 2014 that “numerous” samples of Canada Western Red Spring (CWRS) wheat from the annual Harvest Sample program showed “increased amounts” of mildew damage and were being downgraded.

The commission said it recognized the economic impacts on farmers whose wheat was downgraded, and “anticipat(ed) their concern” by launching a two-year study to make sure the commission’s visual standards were appropriate.

The study assessed falling number, wheat and flour protein, milling yield and water noodle dough colour at two and 24 hours, and included other standard quality tests, the CGC said.

The CGC considers mildew-damaged kernels in a sample to be a “subjective” factor in grading. Mildew’s main impact on milling wheat quality is in reduced flour brightness; a discoloured seed coat also can be an “aesthetic detriment” in food uses such as breakfast cereals.

While moderate mildew damage isn’t considered a major quality factor, the CGC said, it can be considered a “very useful flag” for wet harvest conditions and potential sprout damage.

The commission said its study reviewed samples of all grades of milling wheat from the 2014 and 2015 crop years that were selected, graded and evaluated for mildew content by CGC inspectors.

To make sure mildew was the only factor being evaluated, samples picked for review were ones downgraded based on mildew alone, the CGC said.

The study found “current mildew guides needed to be adjusted to properly convey the intrinsic quality of the wheat and therefore increased presence of mildew.”

The CGC said it also ran tests on the impact of mildew on Canada Western Amber Durum (CWAD) Harvest Sample composites and mildew guides. Tests by the Grain Research Laboratory showed the impact of mildew on semolina quality was “negligible,” the commission said.

The Western Standard Committee’s wheat subcommittee met with CGC officials on Monday to review the study’s results. The subcommittee then recommended mildew guides be adjusted in western milling wheat classes to allow for “increased presence” of mildew in visual standards.

The changes announced Friday now apply to grading in the CWRS, Canada Western Hard White Spring, Canada Western Amber Durum, Canada Western Red Winter, Canada Western Soft White Spring, Canada Western Extra Strong, Canada Prairie Spring White, Canada Prairie Spring Red and Canada Northern Hard Red classes.

Mildew — not to be confused with powdery mildew, a yield-reducing disease that attacks a plant’s leaves — turns up on kernels when field fungi develop under excessive moisture in unthreshed wheat.

Affected wheat kernel samples have grey-to-black mildew spores, typically attached to the brush end of the kernel; that discolouration may eventually extend onto the kernel and into the crease.

The “science-based” change in mildew guidelines “will put money directly back into the pockets of Canadian producers, while maintaining the quality of wheat classes,” the CGC’s acting chief commissioner Jim Smolik said in Friday’s release. — Network

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