Chemical Food Poisoning
Chemical food poisoning results from eating a plant or animal that contains a toxin.
Mushroom (Toadstool) Poisoning: Mushroom poisoning can result from ingesting any of several species of mushroom. The potential for poisoning may vary within the same species, at different times of the growing season, and with cooking. In poisoning caused by many species of Inocybe and some species of Clitocybe, the dangerous substance is muscarine. Symptoms, which begin a few minutes to 2 hours after eating, may include increased tearing and salivation, narrowing (constriction) of the pupils, sweating, vomiting, stomach cramps, diarrhea, dizziness, confusion, coma, and occasionally, seizures. With appropriate treatment, the person usually recovers in 24 hours. Without treatment, death can occur in a few hours.
In phalloidine poisoning, caused by eating Amanita phalloides and related species of mushroom, symptoms start in 6 to 24 hours. People develop intestinal symptoms similar to those of muscarine poisoning, and kidney damage may reduce or stop urination. Jaundice from liver damage is common and develops in 2 or 3 days. Sometimes the symptoms disappear on their own, but about half of the people who have phalloidine poisoning die in 5 to 8 days.
Plant and Shrub Poisoning: This type of poisoning can result from ingesting the leaves and fruits of many wild and domestic plants and shrubs. Green or sprouting underground roots that contain solanine may produce mild nausea, vomiting, diarrhea, and weakness. Fruit of the Koenig tree causes the vomiting sickness of Jamaica.
Seafood Poisoning: Gastroenteritis may be caused by eating bony fish or shellfish. Usually, poisoning caused by eating bony fish results from one of three toxins--ciguatera, tetraodon, or histamine.
Ciguatera poisoning can occur after eating any of more than 400 species of fish from the tropical reefs of Florida, the West Indies, or the Pacific. The toxin is produced by certain dinoflagellates, microscopic sea organisms that the fish eat and that accumulate in their flesh. Larger, older fish are more toxic than smaller, younger ones. The flavor of the fish is not affected. Current processing procedures cannot destroy the toxin. The initial symptoms--abdominal cramps, nausea, vomiting, and diarrhea--may begin 2 to 8 hours after the person eats the fish and last 6 to 17 hours. Later symptoms may include itchiness, a pins-and-needles sensation, headache, muscle aches, a reversal of sensations of hot and cold, and facial pain. For months afterward, the sensations may be disabling.
Tetraodon poisoning from the puffer fish, which is found most commonly in the seas surrounding Japan, is similar to ciguatera poisoning. Death may result from paralysis of the muscles that regulate breathing.
Histamine poisoning from fish such as mackerel, tuna, and blue dolphin (mahimahi) occurs when the tissues of the fish break down after it has been caught, producing high levels of histamine. When ingested, histamine causes immediate facial flushing. It can also cause nausea, vomiting, stomach pain, and hives (urticaria) a few minutes after a person eats the fish. Symptoms usually last less than 24 hours.
Neurotoxin poisoning can occur from June to October, especially on the Pacific and New England coasts. Shellfish such as mussels, clams, oysters, and scallops may ingest certain poisonous dinoflagellates at certain times when the water has a red cast, called the red tide. They produce a toxin that attacks nerves (such toxins are called neurotoxins (see Section 6, Chapter 95)). The toxin, which produces paralytic shellfish poisoning, persists even after the food has been cooked. The first symptom, a pins-and-needles sensation around the mouth, begins 5 to 30 minutes after eating. Nausea, vomiting, and abdominal cramps develop next. About 25% of people develop muscle weakness over the next few hours; occasionally, the weakness progresses to paralysis of the arms and legs. Weakness of the muscles needed for breathing may even be severe enough to cause death.
Contaminant Poisoning: Gastroenteritis may affect people who have ingested unwashed fruits and vegetables sprayed with arsenic, lead, or organic insecticides; acidic fluids served in lead-glazed pottery; or food stored in cadmium-lined containers.
 See the sidebar Chinese Restaurant Syndrome.
Treatment
Most people with chemical food poisoning recover fully and rapidly with nothing more than replacement of fluids and electrolytes. As soon as symptoms begin, a person should try to consume large amounts of fluids. If fluids cannot be tolerated, the person needs to go to an emergency room for intravenous fluid replacement.
If possible, it is often a good idea to rid the stomach of the toxic substance as quickly as possible. For most people, vomiting accomplishes this. Saving a small amount of the first vomitus may be useful if tests are needed later. If a person cannot vomit adequately and symptoms are severe, a doctor may empty the stomach by placing a small tube through the nose or mouth into the stomach. A laxative helps to pass the toxins from the intestines more quickly.
Specific treatments are sometimes given when the toxin is known. For example, atropine is given for certain types of mushroom poisoning. Phalloidine poisoning is treated with a diet high in carbohydrates and sugar given intravenously. Ciguatera poisoning is sometimes treated with mannitol given intravenously. Antihistamines help block the symptoms of histamine poisoning.
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