Grain molds

After insects, grain molds are the most important biotic agents affecting grain storage. Grains usually come contaminated from the field.

Several grain molds are capable of causing foodborne illness. Claviceps purpurea grows on wheat, rye, barley and oats under cool, damp condition.

The attack of molds in the field begins with flowering, grain setting, and grain ripening where the tissues contain ample water, rich in nutrients like sugars, soluble proteins, and amino acids and tender to cause injury.

Molds may grow on mature grains during rainy climate. Molds reduce seed viability, as well as the quality and functionality of grain, and therefore its economic value.

Molds also cause primary and secondary damage. The first is due to the potent lipolytic , amylolytic and proteolytic enzymes that degrade stored nutrients; and the second is due to mycotoxins and changes in grain quality (off-colors, odors, and flavors).

For example, molds attack the developing kernel of sorghum after anthesis and postphysiological maturity, which can seriously degrade the quality of the grain for human food and feed processing, The grain is discolored, has a soft, powdery endosperm, low density, low bulk density and connot be used to produce foods of good quality.

The storage of grain in controlled atmosphere silos has been used to slow mold growth in the grain, Molds are primarily aerobes, but some can grow in anaerobic conditions.
Grain molds