Food toxicity refers to the harmful effects that certain foods or food ingredients can have on the human body. These toxins can be naturally occurring, such as certain types of mushrooms or fish, or they can be the result of contamination or improper preparation. One of the most well-known examples of food toxicity is botulism, which is caused by the bacteria Clostridium botulinum. This bacterium produces a nerve toxin that can cause severe paralysis and even death. Botulism can occur when food is not properly canned or stored, allowing the bacteria to grow and produce the toxin. Another example of food toxicity is the presence of heavy metals, such as lead and mercury, in certain types of fish. These metals can accumulate in the fish's flesh over time and can cause serious health problems if consumed in large amounts. Fish that are known to be high in heavy metals include swordfish, shark, and tilefish. There are also naturally occurring toxins in certain types of mushrooms, such as the death cap mushroom. Consuming just a small amount of this mushroom can cause severe liver and kidney damage, and even death.