Environmental conditions promoting aflatoxin production include which combination?

• A. Low Temperature and High Moisture
• B. Constant Cold and Dryness
• C. High Rainfall with Cool Nights
• D. High Temperature, Drought, High Relative Humidity

Answer: (D)

Aflatoxin production by Aspergillus species is driven by warm conditions, moisture stress, and sufficient humidity to support fungal activity. When temperatures are high, the fungus metabolizes rapidly and toxin synthesis is more likely. Drought stress on the host crop weakens plant defenses and facilitates fungal invasion, so the crop becomes a better substrate for aflatoxin-producing fungi. At the same time, high relative humidity in the environment or storage raises water activity, enabling the fungus to grow and produce toxins. Scenarios that are cool or consistently dry don’t provide the warm, stressed conditions the fungus needs, and very wet but cool conditions don’t meet the temperature or stress requirements as well. Therefore, the combination of high temperature, drought, and high relative humidity best explains conditions that promote aflatoxin production.