Food poisoning refers to illnesses that occur as a result of eating food that is contaminated. The illnesses usually present with symptoms related to food digesting tract (gastrointestinal tract), but infrequently, when complicated can affect other systems in the body. Food poisoning also referred to as food-borne diseases, are mainly caused by bacteria, viruses and parasites. Others are caused by harmful chemicals or toxins that contaminate food such as in mushroom poisoning.

According to Centers for Disease control (CDC), about 76 million food borne diseases occur in the U. S. yearly, most of which have mild symptoms. Up to 325,000 cases require hospitalizations and about 5,000 deaths are attributable to food borne diseases. Severe cases occur in the extremes of age, the very young and old and those who are exposed to high amount of the contaminant.

How does Food get contaminated?

Food contamination can occur during any of the pathways that food must go through before it is eaten.

• When it is been grown till it is harvested: if contaminated manure or water source is used.
• During processing including shipping.
• During handling: especially if food handlers are carriers of bacteria that can be transmitted such as Salmonella. Bacteria can also contaminate foods like salads from contact surfaces.
• During preparation: undercooking may lead to non destruction of microorganisms. There are also some bacteria that survive cooking.
• Improper storage: wrong temperatures, prolonged storage promote contamination. Attention should be paid to recommended temperatures and expiration dates.
• Disregard to simple rules of cleanliness: hand washing prior to food handling cannot be over emphasized.

What are the common symptoms of food poisoning?

Abdominal discomfort and bloating several hours after food is consumed.

Nausea: a feeling of wanting to vomit

Vomiting

Watery stools (diarrhea): with certain types of bacteria may contain mucus and blood

Cramps in the stomach (Abdominal cramps)

Tiredness (fatigue)

Weakness, thirst, and dizziness which could indicate too much loss of water from the body

Fever

Causes of food poisoning

We will discuss viruses and parasites in the write up and bacterial causes of food poisoning will be the focus of part 2 of this write up.

Hepatitis A

Unlike the other types of hepatitis that are transmitted through blood products and sharp objects, hepatitis A is transmitted through food.

Source: raw food, shell fish, fecal contamination of water. Can be transmitted from person to person, hence food handlers are a potential source.

Length of time before symptoms: may take up to twenty eight days.

Presentation: feeling unwell, fever, tiredness, yellowness of the eyes (jaundice) may also occur. It is a self limiting infection in healthy people. However in people who have underlying other types of Hepatitis, infection can be serious.

Testing: Blood test can detect current Hepatitis A infection. Previous exposure with subsequent development of immunity can also be detected.

Prevention: hand washing prior to handling food. Vaccination is available if you are traveling to high area of occurrence. People who have Hepatitis B or C should make sure they are vaccinated for Hepatitis A.

Norwalk- like viruses: Most common viral cause of adult food poisoning.

Source: water, shellfish, and vegetables contaminated with fecal material, food handlers can also transmit it.

Length of time: 12 to 48 hours from time of food consumption.

Presentation: nausea, vomiting, diarrhea, abdominal pain, mild fever and headache. Symptoms self limiting, resolving in about two to three days.

Rotavirus: most common cause of food poisoning in children

Source: fecal contamination of food and shared play areas.

Length of time: 12 to 48 hours

Presentation: since children are often involved, may present as relatively mild to severe illness with vomiting, watery diarrhea and fever.

Testing: routine testing is not compulsory.

Giardia Lambia: is a parasite that causes food poisoning. It is the common agent of traveler’s diarrhea.

Source: ready to eat food and contaminated water often from lakes in the mountainous areas.

Length of time: about 1 to 2 weeks from time of food ingestion.

Presentation: abdominal bloating, watery diarrhea which may last one to two weeks

Testing: parasite can be detected in stool.

Treatment: prescription medications are used. Better to see your doctor if you have diarrhea persist for greater than three days.

Toxic agents causing food poisoning

Mushroom toxins: presentation varies depending on type of mushroom. It can be as mild as nausea, vomiting, diarrhea or with certain types of toxins that affect nerves causing shaking, sweating, hallucinations and at times coma.

Ciguatera poisoning: arises from eating some types of large fish like jacks from tropical waters. It causes numbness around the mouth that can spread to involve arms and legs. Vomiting and muscle pain can also occur.

Take Home Message

Keep your food at required temperature. Maintain basic rules of hand washing hygiene. If you have symptoms suggestive of food poisoning that last more than forty eight hours, do not hesitate to see a doctor. Excessive loss of water from food poisoning can lead to damage of organs in the body, so do not take things for granted if you feel weak, thirsty or dizzy.  

Bacterial causes of  food poisoning will be discussed in Part 2.

Dr. Oluwatoyosi Dairo can be contacted at Amazing Medical Services, 110-16 Sutphin Blvd, Jamaica NY 11435 or by phone at (718) 526 7600. The health columns are for educational purposes only and are not intended to replace the advice of your doctor.

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