Improper handling and storage of cereal grains and oilseeds result in the production of toxins known as aflatoxins which are not generally destroyed by normal cooking process. Aflatoxins are produced by

Aflatoxins are produced by moulds, mainly Aspergillus flavus and Aspergillus parasiticus. These fungi colonise groundnut, maize, cereals and oilseeds when moisture and temperature are not controlled during harvest, drying or storage. That is why the question ties the toxin to improper storage rather than to the crop itself.

Why the other options fail:

• Bacteria: bacteria do produce toxins, such as botulinum toxin, but aflatoxin is a fungal secondary metabolite, so this is not the source.
• Protozoa: these single-celled organisms cause diseases like malaria and amoebiasis. They are not producers of mycotoxins in stored grain.
• Viruses: viruses lack the metabolic machinery to synthesise such compounds. They replicate inside host cells.

The core concept is post-harvest food safety. It links to the Mains GS-III theme of storage losses and the role of warehousing and FCI. Aflatoxin B1 is classed by IARC as a Group 1 human carcinogen, and the Food Safety and Standards Act, 2006 sets permissible limits.

Trap: aspirants see 'toxin' and pick bacteria, forgetting that mycotoxins like aflatoxin are a separate category from bacterial toxins.