I speak about it often, not many people know about it. Please read this article carefully or you could be eating poison!

Sadly the world’s fruits and vegetables and grains are getting infected with toxins. This is not a joke, I smell it everywhere I go, its name is Aspergillus. Recently in a Michelin kitchen the paper towels were contaminated, I could smell it immediately. I am not surprised when I encounter Aspergillus, after it took me 14 years to discover it.

http://en.wikipedia.org/wiki/List_of_food_contamination_incidents

The native habitat of Aspergillus is in soil, decaying vegetation, or in vegetables, fruits, and grains undergoing microbiological deterioration. This invades all types of organic substrates whenever conditions are favorable for its growth. Favorable conditions include high moisture content and warm temperatures.

Many fruits are stored in dark places after harvest, held in container or in a warehouse until they are ready. When I say ready, I mean these fruits are picked unripe, held and gassed with Ethylene to ripen them. This is done according to their demand in the market. During the holding process this is where Aspergillus breeds and contaminates. Ethylene gas is used commercially to ripen tomatoes, pears, pineapples, banana and other fruits post-harvest.

Sites for reference:

http://en.wikipedia.org/wiki/Aflatoxin
http://ehtrust.org/fact-sheets-facts-about-aflatoxin