Aflatoxins are produced by molds, specifically certain species of Aspergillus fungi. These molds commonly contaminate crops such as cereal grains (e.g., maize, wheat, rice), oilseeds (e.g., peanuts, cottonseed, sunflower seeds), and various other agricultural products. Improper handling and storage conditions, including warm and humid environments, can promote the growth of Aspergillus molds and the production of aflatoxins.

It is important to note that aflatoxins are not produced by bacteria, protozoa, or viruses, but rather by certain species of molds in the Aspergillus genus, particularly Aspergillus flavus and Aspergillus parasiticus. These molds can produce aflatoxins under specific conditions, and the toxins can pose significant health risks if consumed in contaminated food products.