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What is Food Poisoning?

rchuaBy Philip S. Chua, M.D., FACS, FPCS

Food poisoning is a variety of illnesses caused by eating food contaminated with bacteria, toxins or chemicals. The symptoms usually include diarrhea, abdominal pains and vomiting. The diarrhea and vomiting could be so severe as to cause extreme dehydration, which, if untreated and unabated, could be fatal.

How does bacterial  contamination occur?

Raw food may have bacteria in it or may be contaminated by unsanitary handling. These bacteria then grow and multiply, and when the “infected” food is eaten, the growth and multiplication of the bacteria continue in the stomach or bowel, producing symptoms of food poisoning. This leads to abdominal pains, diarrhea and vomiting, which are part of the body’s defensive ways of getting rid of the offending bacteria. The most common bacteria causing food poisoning is Listeria Salmonella, usually from poultry or infected eggs, specifically duck eggs), Clostridia (contamination by dirt or flies), and Shigella and Escherichia coli (fecal contamination of food and/or water).

 

What about toxins?

Food that is kept in a warm place, or improperly preserved, can produce chemicals called toxins. One of the commonest is the Staphylococci toxin from Staphylococci bacteria that can be transmitted by a food careless handler with a boil or infected wound full of the Staph bacteria. Botulism (due to Clostridium Botulinum), from badly tinned or bottled food, is not very common but can be fatal. When the contaminated food is ingested, severe gastrointestinal symptoms may occur.

 

What chemical poisons are found in food?

There are some common food items that contain natural chemical poisons. Some fungi are very poisonous even when eaten in tiny quantities, causing irregular heart beat, coma or even death. The green areas on potatoes which have been exposed to the light, uncooked kidney beans, some nuts, etc. contain poisonous chemicals, which can cause symptoms of food poisoning if inadequately cooked. Not properly washing fruits and vegetables that are contaminated with pesticides can also cause food poisoning. Some mushrooms are poisonous and not edible.

 

What bacteria grows  on cooked rice?

Bacillus cereus thrives and multiples in cooked rice and can cause food poisoning. The bacteria produces chemical toxin which is very resistant and not destroyed even by high temperatures. The best way to prevent this is by refrigerating left over rice, which should be consumed within 48 hours.

 

How soon do the  symptoms appear?

The symptoms of food poisoning usually start fairly suddenly with abdominal pains, frequently cramping in nature and soon followed by diarrhea. The pains can be persistent for a few days and become worst before an episode of diarrhea or vomiting. Throwing up may cease after a few hours but the diarrhea may continue for days. If the illness is due to bacterial contamination, the symptoms appear about 12-24 hours after ingestion, but if it is due to toxins, the onset of symptoms comes rapidly, usually within minutes after eating the contaminated food.

Severe Botulism begins after about 12 hours with vomiting, abdominal cramps, and may culminate in paralysis and coma.

 

Is Food Poisoning  dangerous?

Obviously, yes, as discussed above. In young children and among the elderly, dehydration is the main danger. Vomiting and diarrhea can result in a rapid loss of body fluids and electrolytes. This can disrupt the very delicate chemical balance in the body and, if not treated early, can lead to coma and even death. Botulinum and Staph toxins are in themselves dangerous, and the poisoning can be fatal, if not managed in a timely and proper fashion.

 

How do we prevent food poisoning?

Good environmental and personal hygiene, proper food preparation, handling and storage, avoidance of questionable food (fruit or potato salad and dishes sautéed with tomato that have been exposed for more than an hour at a party or picnic under hot weather, mussels and other shelled foods that remain closed after cooking, poultry or meats (hamburgers, etc) that are not thoroughly cooked, and can goods that are of questionable freshness, that are “expired,” or with bulging top, are some basic preventive measures that can be taken to prevent food poisoning. The prudent practice and common sense dictum is “if in doubt, discard.”

 

What is the mainstay  of therapy?

This depends on the cause of the food poisoning: bacteria, toxin or chemical. But basically, oral and/or intravenous fluid replacement is the key to prevent further dehydration from fluid and electrolyte loss from diarrhea and vomiting, which could be life-threatening. Young children and the elderly can become very ill fast, since they succumb rapidly to dehydration, so medical consultation, or even hospitalization, may be needed early. Antibiotics may be given where indicated to clear up the infection, but as a rule they are usually not used because they may sometimes worsen the condition. Fortunately, most of the food poisoning cases respond well to fluid replacement. Possible botulism  patients should be hospitalized without delay. The stomach may be pumped out and botulism anti-toxin given to counteract paralysis.

Those who are very ill may need ventilator support in the ICU. An antidote may be needed for fungal food poisoning. All the evaluation and decision on the management are best handled by the attending physician.

After surviving the acute stage, the patient is expected to recover fully with excellent prognosis. However, just like most other illnesses, food poisoning is best prevented. In majority of situations, this is within our power.

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