Thermomyces lanuginosus

Thermomyces lanuginosus is a thermophilic fungus widely recognized as a major agent of deterioration in stored agricultural products, especially under high-temperature conditions.

This fungus is characterized by its ability to thrive at temperatures between 45 and 55 degrees Celsius, making it a primary culprit in the self-heating process of grain stores.

Biologically, it acts as a saprotroph that secretes potent enzymes such as lipases and proteases, which effectively break down complex organic materials like starch and protein.

The fungus produces a thick, woolly mycelium, which starts as a white to cream-colored growth and may darken during sporulation as the colony matures.

It is ubiquitous in the environment, with spores commonly present in soil, field debris, and dust, allowing it to easily colonize harvested grain if storage conditions are neglected.

The primary driver for the growth of Thermomyces lanuginosus is the combination of high moisture content in stored crops and a significant increase in internal temperature.

Poor aeration in grain silos creates stagnant heat pockets, providing the ideal environment for the fungus to multiply rapidly through its metabolic activity.

The presence of fine particles, weed seeds, and damaged grains in the bulk storage acts as a nursery, as these materials accumulate moisture faster than sound kernels.

Once the initial colonization begins, the fungal metabolic heat contributes to further temperature increases, creating a feedback loop that accelerates the spoilage of the entire grain batch.

Extended storage times without proper turnover or ventilation significantly increase the risk of massive infection by this pathogen in industrial settings.

Thermomyces lanuginosus causes substantial economic losses by reducing the dry matter of grain and decreasing its nutritional value for feed and human consumption.

The infestation leads to severe organoleptic changes, including a foul, musty odor and visible discoloration, rendering the product unmarketable and unsuitable for processing.

The metabolic activities of the fungus can lead to the production of heat-stable enzymes and potential mycotoxins, posing health risks to livestock and potentially humans.

Seed viability is severely compromised, meaning that heavily infected grain cannot be used for planting, resulting in a loss of valuable genetic resources.

Large-scale contamination in silos often leads to the complete disposal of entire batches, creating significant financial burdens for farmers and grain storage facilities.

Prevention starts with efficient post-harvest drying, ensuring that the moisture content of grain is kept below safe levels to inhibit microbial activity.

Installing high-quality aeration systems is essential to maintain uniform temperatures within storage structures and prevent the buildup of heat spots.

Rigorous pre-storage cleaning processes must be implemented to remove debris, dust, and damaged seeds that serve as primary substrates for fungal growth.

Continuous monitoring using temperature sensors allows for early detection of potential self-heating, enabling prompt intervention before the infection spreads.

• Strict moisture level management (below 14%).
• Routine grain aeration and turnover cycles.
• Comprehensive disinfection of empty storage bins.
• Use of moisture and temperature monitoring telemetry.