Microbes and food 5. Food poisoners
5.3 Fungi
Mouldy peanut photo
Picture 2.3a A mouldy peanut. The filaments can produce aflatoxins which can cause cancer.
Mouldy food can be dangerous to eat if the fungi growing on it are the kind that produce mycotoxins. These are formed as the branching network of fungal filaments (hyphae) spread through the food and break it down.

Moulds can grow in drier environments than other microbes and mycotoxins are a problem in products such as nuts and cereals which have been stored in damp conditions. It's easy to mistakenly process and eat contaminated food because it does not look spoilt. Very small amounts of mycotoxins can make people ill.

The levels of mycotoxins in certain products are controlled by law in many countries.

Some mycotoxins are:

  • Aflatoxinscarcinogens found in mouldy nuts.
  • Ochratoxins – cause kidney disease and are produced in cereals such as maize and barley.
  • Patulin – associated with mouldy apples and poisoning has arisen from drinking contaminated fresh apple juice.
Death Angel photo
Picture 2.3b Whilst some mushrooms are safe to eat and tasty, others, like the Death Angel can be deadly.
Mushrooms and toadstools
These fruiting bodies of certain fungi have been part of the human diet for centuries. However, not all of them are edible.

Some, such as the aptly named Death Angel (Amanita bisporigera), contain poisonous compounds which can be lethal. Other species cause unpleasant effects: sickness, diarrhoea, kidney and liver damage. Before you eat wild mushrooms you should have them checked for safety by an expert.