Food poisoning is a type of illness caused by eating food that is contaminated with infectious substances, such as bacteria and viruses, or toxic matter. The toxic contaminants in food can include poisonous by-products of bacteria and other organisms or they can be from chemicals or naturally occurring substances. According to the Mayo Clinic, the most common source of food poisoning is infectious organisms.
One cause of toxic food poisoning is food that has been improperly stored or handled and has been adulterated with such poisons as cleaning solutions or insecticides. To prevent this problem, food should always be kept covered and placed in the refrigerator or in a cupboard or pantry that does not contain anything but food. Always follow instructions on chemicals used around food and discard any food that comes in contact with substances that may be harmful.
Toxic food poisoning can also result from eating certain foods where the toxin is produced by various organisms. This is common with certain types of fish, including shellfish, barracuda, fresh tuna, and mackerel. The toxins are most often produced by the bacteria and are found in certain fish; they can be impossible to detect. Unlike illness caused directly by living organisms, chemical sources of toxic food poisoning normally cannot be removed by cooking. Safe handling of the fish is the best insurance against these problems, and fish should never be purchased from questionable sources.
Symptoms of toxic food poisoning can occur very quickly after the food is ingested, or it may take several days to show up. Signs typically include vomiting, diarrhea, headache, and intense stomach pain. Depending on the chemicals involved, toxic food poisoning can also include burning of the mouth and throat, a rash, or excessive sweating.
Sometimes, there is no effective treatment for toxic food poisoning, but mild cases usually resolve themselves in a day or two at home without any special care. The main concern is most often dehydration, which can be serious and in some cases even fatal, especially to the very young and very old. Patients dealing with toxic food poisoning are typically advised to take small sips of a beverage containing electrolytes, if their condition allows.
Those that cannot retain fluids may require medical attention, especially if the person becomes lethargic or is ill for more than three days. Other signs that indicate an immediate need to see a doctor include vomiting blood or blood in the stool, difficulty swallowing, or trouble speaking. Patients may be asked to contact the health department or other local health authority to report any cases of toxic food poisoning that may have come from a restaurant or other public source, or if the source is unknown.