Natural Toxins In Food

What are natural toxins?

  • Natural toxins are toxic compounds that are naturally produced by living organisms.
  • These toxins are not harmful to the organisms themselves but they may be toxic to other creatures, including humans, when eaten.
  • These chemical compounds have diverse structures and differ in biological function and toxicity.
  • Some toxins are produced by plants as a natural defense mechanism against predators, insects or microorganisms.

1. Aquatic bio toxins

  • Toxins formed by algae in the ocean and fresh water are called algal toxins.
  • Algal toxins are generated during blooms of particular naturally occurring algal species.
  • Shellfish such as oysters are more likely to contain these toxins than fish.
  • Algal toxins can cause diarrhea, vomiting, tingling, paralysis and other effects in humans, other mammals or fish.

2. Cyanogenic glycosides

  • Cyanogenic glycosides are phyto toxins (toxic chemicals produced by plants) which occur in at least 2000 plant species, of which a number of species are used as food in some areas of the world.
  • Cassava, sorghum, stone fruits, and almonds are especially important foods containing cyanogenic glycosides.

In humans, the clinical signs of intoxication can include:-

  • Rapid respiration, drop in blood pressure, headache, stomach pains, vomiting, diarrhea, mental confusion, followed by coma.

3. Furocoumarins

  • These toxins are present in many plants such as  citrus plants (lemon, lime) and some medicinal plants.
  • Furocoumarins are stress toxins and are released in response to stress, such as physical damage to the plant.
  • Some of these toxins can cause gastrointestinal problems in susceptible people. Furocoumarins are phototoxic, they can cause severe skin reactions under sunlight (UVA exposure).

4. Lectins

  • Many types of beans contain toxins called lectins, and kidney beans have the highest concentrations – especially red kidney beans.
  • Few as 4 or 5 raw beans can cause severe stomachache, vomiting and diarrhea.
  • Lectins are destroyed when the dried beans are soaked for at least 12 hours and then boiled vigorously for at least 10 minutes in water.
  • Tinned and canned kidney beans have already had this process applied and so can be used without further treatment.
Red Kidney Beans

5. Solanines and chaconine

  • All solanacea plants, which include tomatoes, potatoes, and eggplants, contain natural toxins called solanines and chaconine.
  • Higher concentrations are found in potato sprouts and bitter-tasting peel and green parts, as well as in green tomatoes.
  • To reduce the production of solanines and chaconine it is important to store potatoes in a dark, cool and dry place, and not to eat green or sprouting parts.
Potato Sprouts

6. Poisonous mushrooms

  • Wild mushrooms may contain several toxins, such as muscimol and muscarine, which can cause vomiting, diarrhea, confusion, visual disturbances, salivation, and hallucinations.
  • Onset of symptoms occurs 6–24 hours or more after ingestion of mushrooms. Fatal poisoning is usually associated with delayed onset of symptoms which are very severe, with toxic effect on the liver, kidney and nervous systems.
Wild Mushroom

The world’s most poisonous mushroom

Amanita phalloides

  • Amatoxins in Amanita phalloides, commonly known as the death cap mushroom, are responsible for 90% of the world’s mushroom-related fatalities.
Amanita phalloides

7. Mycotoxin

  • A mycotoxin is a toxic secondary metabolite produced by organisms of the fungus kingdom and is capable of causing disease and death in both humans and other animals.
  • The term ”mycotoxin” is usually reserved for the toxic chemical products produced by fungi that readily colonize crops.

8. Puffer fish

  • The Puffer fish is considered the second most poisonous vertebrate on Earth. (First prize goes to the tiny golden poison frog  of Colombia)
  • The toxin responsible for puffer fish’s deadly character is called tetrodotoxin.
  • It’s found in the puffer fish’s skin, its liver & reproductive organs.
  • Tetrodotoxin is a neurotoxin.
  • Almost all puffer fish contain tetrodotoxin, a substance that makes them foul tasting and often lethal to fish.
  • To humans, tetrodotoxin is deadly, up to 1200 times more poisonous than cyanide. There is enough toxin in one puffer fish to kill 30 adult humans, and there is no known antidote.
  • Chef must have special license to cut this fish and chef must be well trained. (more about puffer fish)

How can people minimize the health risk from natural toxins?

When it comes to natural toxins it is important to note that they can be present in a variety of different crops and foodstuff.  In a usual balanced, healthy diet, the levels of natural toxins are well below the threshold for acute and chronic toxicity.

  • Not assume that if something is ‘natural’ it is automatically safe.
  • Throw away bruised, damaged or discolored food, and in particular mouldy foods.
  • Throw away any food that does not smell or taste fresh, or has an unusual taste.
  • Only eat mushrooms or other wild plants that have definitively been identified as nonpoisonous.


05/05/2020 by @cheflakey

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