Ergot

Definition

Ergot is defined in the glossary section of the Official Grain Grading Guide as a fungal disease which occurs on cereals and grasses. It is most prevalent on rye, triticale, wheat, and barley, in decreasing order of occurrence. It is rarely found on oats. The disease produces hard, dense fungus bodies, called sclerotia, having a purplish black exterior, a purplish white to off-white interior, and a relatively smooth surface texture.

Photographs

Ergot bodies, sizes and shapes. This includes a cross-sectioned kernel to show white interior
Different sizes and shapes of ergot bodies, including one that has been cross-sectioned to show its white interior.
Ergot-infected wheat head, as the kernel grows the ergot affects the body.

A comparison of wheat kernels to ergot bodies.

As seen on the wheat head, an ergot body replaces the affected kernel as it grows, resulting in an ergot body that is similar in sizeand shape to the kernel it replaced.

Procedure for assessment

Ergot is considered an objective grading factor with assigned percentages in each grade. To assess the percentage of ergot that remains in the sample after cleaning*, the inspector performs a physical separation. The number of grams utilized to perform the assessment is predetermined and defined in the Official Grain Grading Guide. The inspector will then apply the tolerances as set out in the Grade Determinant Tables found in the Official Grain Grading Guide.

*Ergot is not easily cleaned from a sample of grain, since normal cleaning equipment separates foreign material by size and shape.

Cause

Ergot is a fungal parasite (Claviceps purpurea) of cereals and grasses (Lorenz 1979). Infection takes place at the flowering stage. Ergot is most prevalent in years when continuous moist conditions prevail during both stages of the disease cycle.

End-use issues

Ergot contains alkaloids, which may be toxic when ingested by animals, poultry or humans (Mantle, 1977a, b). In recognition of its toxicity, and that the alkaloids can remain stable among final end-products, strict tolerances for ergot are universally required when marketing grain. Sclerotia can also cause specks in flour and pasta products.

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