Your probably right, I might be over stating it, but alfatoxins found in peanuts even in trace amounts are a real danger to fish you would be surprised just how little is required to kill.
Peanuts, groundnuts, monkeynuts or whatever you want to call them (technically a legume) are particularly susceptible to contamination during growth because they lay just below the soils surface where it is warm and humid - favourable conditions for mould growth.
Normal processing will not destroy the aflotoxins (seemingly only irradiation or very high protein destroying temperatures are needed), prolonged storage to reduce water content leads to even more severe infection by the mould fungus aspergillus flavus favouring a more mildly humid environment, releasing the toxic and highly carcinogenic substance aflatoxin. Storage of peanuts reduces the water content which ordinarily eradicates a large proportion of the mould but the toxin is the real killer and remains active despite this.
Yes it is found in other foods such as corn and grain as you say, but in negligible amounts. I think it has something to do with the fact that anything plucked out of the ground will deteriorate faster than a food that grows from it suggesting that the conditions just below the surface are optimal for fungal/mould growth.
BTW rejected peanuts (poorest quality with obvious mould growth and those found to be contaminated) are routinely used to make peanut oil (the original diesel engine fuel) and are sometimes resold through intermediaries (apparently checks are done only on the raw nut product).
I know of two UK bait companies that use the oil and only one as far as I know sells a nut paste the last time I checked, there may be more but its not surprising considering the nutritional value that fish find attractive in peanuts.
Considering that China is the largest grower accounting for nearly half of worlds production, surprisingly they consume most of it themselves, probably because of the higher incidences of contamination of stock piling and fewer quality control measures means they are unable to export?
The oil is also used for biodiesel production (which I was involved in a few years ago as a private venture dealing in methanol and titration liquids) and its waste derivatives glycerol can be converted to propylene glycol, which in my opinion is the cheapest (and most common) liquid carrier additive used for artificial food colours and flavourings, also propylene glycol is known to exert a higher level of biochemical oxygen demand (BOD) during degradation in surface waters than raw sewage but that's another story.
Back to the nuts...
Peanuts kill in other ways not previously known to science.
After more than two years of investigation involving six major US laboratories, including one in London, the cause for bird death was diagnosed as not being caused by ingestion of peanuts contaminated by alfatoxins, but containing a fungus produced poison attributed to the mould Fusarium Compactum, which produces a deadly toxin under cold, wet conditions that previously was unknown to science prior to 1985.
Introducing peanuts in "cold wet conditions"... apart from my dogs nose what else is cold and wet I wonder?
Seriously though, the dangers of peanuts introduced into our cold waters (or left out for the birds) cannot be over stated!
