What is Food Poisoning?
Food poisoning refers to a stomach and intestinal illness caused by consuming food or drinks contaminated with bacteria, viruses, or toxins. Symptoms often begin within hours of eating contaminated food and typically include nausea, vomiting, stomach cramps, and diarrhea. Most cases of food poisoning last from a few hours to a few days1,2 and often resolve without medical treatment. However, in severe cases, it can result in long-term health problems or even death.
Symptoms of Food Poisoning
Food poisoning symptoms can range from mild to severe and are often similar to those of gastroenteritis. However, unlike gastroenteritis, food poisoning symptoms typically appear suddenly and dramatically, usually within 1-6 hours after ingestion1. Symptoms tend to fluctuate quickly. Depending on the type of food poisoning, one or more of these symptoms may occur:
- Nausea
- Vomiting
- Diarrhea
- Abdominal pain or cramps
- Headache
- Fever or chills
- Loss of appetite
- Fatigue
- Weakness
Food poisoning can become life-threatening. Seek medical attention immediately if you experience:
- A very high fever (38°C or higher)
- Blood in urine
- Blood or mucus in vomit or diarrhea
- Diarrhea lasting more than 3 days
- Frequent vomiting
- Inability to keep fluids down for more than 24 hours after becoming ill
- Signs of severe dehydration, such as a dry mouth, low urine output, dizziness, and weakness4.
How Long Does Food Poisoning Last?
The duration of food poisoning varies depending on the cause but usually lasts between 24-48 hours4. Symptoms may subside within a few hours or persist longer depending on the amount of contaminated food consumed, the type of bacteria or toxin involved, and the severity of the symptoms. If symptoms last longer than 3 days, it’s essential to seek medical help immediately.
What Causes Food Poisoning?
While raw chicken or spoiled seafood are commonly associated with food poisoning, there are many potential causes. These can include:
- Salmonella
Associated Foods: Raw chicken and meat, undercooked or raw eggs, raw fruit or vegetables.
- Campylobacteria
Associated Foods: Raw poultry and meat, contaminated water, unpasteurized dairy products.
- Listeria
Associated Foods: Soft cheese, deli meat, unpasteurized dairy, raw produce, poultry.
- Norovirus
Associated Foods: Raw produce and shellfish from contaminated water, or contaminated by an infected food handler.
- Rotavirus
Associated Foods: Raw produce. Can be spread through person-to-person contact, contaminated by an infected food handler, or by sharing food or utensils with someone who is ill.
- E. coli (Escherichia coli)
Associated Foods: Undercooked ground beef which has been contaminated with feces during slaughter, undercooked meat, apple cider, unpasteurized milk, sprouts, contaminated water.
- Giardia
Associated Foods: Uncooked food, fruit or vegetables or infected water.
- Cryptosporidium
Associated Foods: Uncooked food, fruit or vegetables.
- Shigellosis
Associated Foods: Seafood or raw produce. Can be spread by a contaminated food handler.
- Vibrio vulnificus
Associated Foods: Raw or undercooked shellfish or spread through contaminated seawater.
- Certain wild mushrooms, such as Deathcap mushrooms, which are extremely poisonous, avoid consuming any mushrooms unless they are properly identified as safe. Seek emergency medical care if you suspect you have eaten a poisonous mushroom5.
How Does Food Become Contaminated?
Food contamination occurs when food is improperly handled, stored, or cooked. Contaminants such as bacteria can either multiply to dangerous levels or release toxins as they grow, causing illness. Common causes of contamination include:
- Not washing hands properly or using unclean utensils during food preparation, which can transfer bacteria from feces or raw meat
- Storing food at unsafe temperatures, allowing bacteria to multiply
- Cross-contamination from raw meats coming into contact with ready-to-eat foods
- Reheating leftovers multiple times, allowing bacteria to multiply when the food is heated above 5°C
- Not cooking food, particularly meat, at high enough temperatures
- Fresh produce, eggs, or water contaminated by animal manure
- Exposure to pets, flies, or pests
- Contact with someone ill from viral gastroenteritis6.
Who is at High Risk for Food Poisoning?
Certain people are more vulnerable to serious complications, especially those with weakened immune systems. High-risk groups include:
- Elderly individuals
- Infants or babies
- Pregnant women (since listeria can cause miscarriage)
- People with chronic illnesses or compromised immune systems
How to Prevent Food Poisoning
To minimize the risk of food poisoning, it’s crucial to follow proper food safety practices2:
- Wash hands thoroughly with soap and water before and during food preparation
- Clean utensils, surfaces, and chopping boards frequently
- Separate raw foods from ready-to-eat items and ensure they are prepared on different surfaces
- Cook food to safe temperatures, using a food thermometer to ensure proper cooking
- Refrigerate or freeze perishable foods promptly to prevent bacterial growth
- Always check the expiration date on food products
- When in doubt, discard questionable food
How to Treat Food Poisoning
While food poisoning can be uncomfortable, most cases resolve fairly quickly. To help ease the symptoms while recovering, consider the following:
- Rest at home
- Drink water or sip on ice cubes if you’re having difficulty keeping liquids down
- Use oral rehydration solutions or electrolyte drinks to replenish lost fluids
- Eat bland, easily digestible foods
- Avoid using anti-vomiting or anti-diarrhea medications unless advised by your doctor, as these could hinder your body’s ability to expel toxins
If your symptoms appear to resemble viral gastroenteritis, which is infectious, it’s essential to avoid preparing food or interacting with others until you feel better.
When to See a Doctor
Food poisoning usually resolves without medical intervention. However, if you are elderly, pregnant, or very young, it is important to consult a doctor. In the case of children, contact your doctor if:
- Your child’s diarrhea lasts more than a few days
- The child has bloody diarrhea
- The child shows signs of dehydration and is unable to keep liquids down
Visit an emergency department if:
- Symptoms are affecting a child under 12 months
- The child is vomiting, unable to keep fluids down, and experiencing severe abdominal pain
- The child exhibits signs of dehydration, such as low urine output, lethargy, or extreme thirst
In adults, see your doctor if:
- Symptoms persist after three days
- Vomiting continues for more than 24 hours
- Your vomit or diarrhea contains blood or mucus