How do molds and fungi spoil stored cereals?

Molds and fungi spoil stored cereals primarily through contamination and the production of toxic metabolites. These microorganisms, which are multicellular fungi that reproduce via spores, can contaminate grain during harvest, storage, or distribution.12

Spoilage Mechanisms

• Growth Conditions: Fungi thrive in environments with favorable moisture levels and temperatures. If the moisture content of stored grain exceeds 16 percent, the resulting heat and respiration create an environment that promotes fungal growth. Molds generally require a water activity level of at least 0.8 to grow.31
• Mycotoxin Production: Certain microfungi produce mycotoxins, which are toxic metabolites that pose significant health risks to humans and livestock. These toxins can cause severe health issues, including liver damage, neurological disturbances, and cancer. Common examples include aflatoxins, produced by Aspergillus species, and deoxynivalenol, produced by Fusarium species.4
• Infection: Fungi can also infect the plant itself, such as ergot, which infects rye and can lead to widespread food poisoning if contaminated grain is consumed.5

To mitigate these risks, storage facilities focus on maintaining low moisture content and proper ventilation to dissipate heat and prevent the conditions necessary for fungal proliferation.3