Food poisoning is a group of symptoms that occur after consuming food contaminated with harmful pollutants such as bacteria or viruses. In some cases, it can be fatal. It is often associated with improperly canned or preserved foods, as well as honey, processed meats, and fermented, smoked, or salted fish. There are various causes of food poisoning.
Symptoms include cramps, vomiting, breathing problems, difficulty swallowing, blurred vision, weakness, or paralysis.
In this article, we will review the most important types of bacterial and viral contaminants that cause food poisoning, and the foods through which they are transmitted.
Causes of Food Poisoning
1. Salmonella Bacteria
Transmission Sources:
Poultry and Eggs
Salmonella bacteria can contaminate any food, but animal products pose a greater risk due to contact with animal feces.
In chickens, the bacteria can infect the egg before the shell forms, which means even clean, fresh eggs may contain Salmonella.
Symptoms include stomach cramps, fever, and diarrhea 12 to 72 hours after exposure. The illness usually lasts 4 to 7 days.
Prevention and Safety Tips:
Do not eat raw or undercooked eggs.
Cook poultry to 165 °F.
Keep raw poultry separate from cooked poultry and other foods.
Wash hands, cutting boards, utensils, and surfaces after use.
Fresh Vegetables
Fresh produce such as vegetables can also cause Salmonella infections.
Most outbreaks have been linked to contaminated tomatoes, chili peppers, leafy greens, and papayas.
Sprouts may also contain Salmonella because they grow in warm, humid conditions — and are often eaten raw or lightly cooked.
The infection can be severe or even fatal in vulnerable groups such as children and the elderly.
Prevention and Safety: Wash and dry vegetables thoroughly and store them in the refrigerator at 40 °F.
Processed Foods
Chips, crackers, soups, peanut butter, and even frozen meals may pose a slight risk of Salmonella infection.
Outbreaks have been linked to peanut butter and packaged foods made from peanuts.
Salmonella can contaminate many other products in a factory, leading to recalls.
Prevention and Safety: Heating food well to 165 °F can kill Salmonella.
Raw Meat
Raw meats, especially ground meat, are at risk of Salmonella contamination. Ground turkey has been associated with several outbreaks.
You usually can’t tell if the food is contaminated because it smells normal.
Prevention and Safety:
Cook beef and lamb to at least 145 °F.
Cook poultry (including ground poultry) to at least 165 °F.
Heat ground beef and lamb to 160 °F.
Avoid cross-contamination by washing hands and all surfaces with warm water and soap after touching raw meat.
2. Escherichia coli (E. coli)
Transmission Sources:
Ground Meat
E. coli lives in the intestines of cattle and can contaminate beef during slaughter.
Ground meat is particularly risky because the bacteria can spread even when the meat looks cooked on the outside.
Symptoms of E. coli infection include severe abdominal cramps, watery diarrhea, and vomiting.
The illness usually develops a few days after exposure and can be severe in vulnerable groups. It typically lasts about a week.
Prevention and Safety:
Cook meat thoroughly to 160 °F until no pink color remains.
Do not place cooked burgers back on plates that held raw meat.
Wash utensils with warm, soapy water.
Unpasteurized Juices and Milk
Most juices sold in grocery stores are pasteurized and pose no risk.
However, unpasteurized juices and apple cider sold at farms or health food stores can cause E. coli infection.
Bacteria can also enter raw milk through unclean milking equipment or contaminated udders.
Pasteurization uses heat to kill bacteria.
Prevention and Safety: Only buy pasteurized or sterilized products. Raw milk should be boiled before drinking.
Fruits and Vegetables
Fruits and vegetables can become contaminated if the fertilizer or water used to grow them contains E. coli.
Leafy greens are particularly at risk; outbreaks have been linked to fresh spinach.
Nevertheless, experts emphasize that the health benefits of consuming fruits and vegetables far outweigh the risk of food poisoning.
Prevention and Safety: Separate and wash leafy greens individually. Cooking leafy greens kills bacteria.
3. Clostridium perfringens Bacteria
Transmission Sources: Stews, meat, and gravy.
Clostridium perfringens causes cramps and diarrhea that last less than 24 hours.
Stews, gravies, and other foods prepared in large quantities and kept warm for long periods before serving are common sources.
Prevention and Safety: Cook stews, sauces, and gravies thoroughly, then keep them above 140 °F or below 41 °F, and serve hot immediately after cooking.
4. Staphylococcus Bacteria
Transmission Sources: Sandwiches, salads, and pastries.
Staphylococcal infections occur when food is prepared by someone who is infected — especially if they have an open wound or skin infection on their hands.
High-risk foods include sandwiches and salads (with eggs, tuna, chicken, potatoes, or pasta) and cream-filled pastries and desserts.
Symptoms appear quickly — within 30 minutes — and include vomiting, cramps, and diarrhea.
The illness usually begins within one to three days.
Prevention and Safety:
Wash hands thoroughly before preparing food.
Do not prepare food if you are sick, have a nasal or eye infection, or have an open wound or hand infection.
5. Hepatitis A Virus: Contaminated Food
Hepatitis A is a virus that attacks the liver, causing fever, fatigue, nausea, weight loss, and jaundice. Most cases are mild.
It spreads when an infected person does not wash their hands properly and then touches food or items that go into the mouth.
Prevention and Safety:
Get vaccinated against Hepatitis A, especially if traveling to a country where it is common.
Wash your hands thoroughly before touching or eating food.
6. Campylobacter Bacteria
Transmission Source: Undercooked poultry.
Even a small amount of raw chicken can cause a Campylobacter infection.
It is the second leading cause of food poisoning in the United States.
Symptoms include fever, cramps, often bloody diarrhea, and sometimes vomiting. Not everyone experiences diarrhea or vomiting.
Most people recover within a week, but the infection can lead to Guillain–Barré syndrome — a rare, serious illness that develops weeks later and can cause temporary paralysis.
Prevention and Safety:
Avoid contamination by washing hands, surfaces, and utensils with warm, soapy water after touching raw poultry.
Cook poultry to at least 165 °F.
7. Norovirus
Transmission Source: Contaminated food.
Noroviruses are the most common cause of what we often call “stomach flu.” They cause vomiting and watery diarrhea, typically lasting 24 to 48 hours.
Food becomes contaminated when food handlers do not wash their hands after using the restroom.
Salads and raw shellfish are especially risky because they are not cooked before consumption. The virus usually spreads from person to person.
Prevention and Safety: Wash hands with hot water and soap for 30 seconds after using the toilet, changing diapers, and before handling food.
8. Vibrio vulnificus Bacteria
Transmission Source: Raw shellfish.
This bacteria lives in warm seawater and can contaminate shellfish, causing gastrointestinal symptoms similar to other foodborne illnesses.
In people with weakened immune systems, it can lead to life-threatening bloodstream infections.
Prevention and Safety:
Eat only well-cooked shellfish.
Frying, boiling, and steaming reduce the risk of infection.
Discard any shellfish that do not open during cooking.
9. Paralytic Shellfish Poisoning (PSP)
PSP toxins are produced by certain types of algae.
When these algae “bloom” — known as red tide — they produce high levels of toxins that can contaminate shellfish.
Symptoms include tingling lips and tongue, difficulty breathing, and eventually paralysis.
Death can occur within 30 minutes of severe exposure. Fortunately, PSP is very rare.
Shellfish are regularly tested for toxins before being sold to the public.
10. Scombrotoxin (Scombroid Poisoning)
Transmission Source: Fresh tuna.
This reaction resembles an allergic response caused by eating fish that has started to spoil.
Fish commonly associated with this toxin include tuna and mackerel.
As the fish begins to deteriorate, bacteria produce histamine, leading to a burning sensation in the mouth, rashes, dizziness, headache, and diarrhea.
Symptoms usually subside within 4 to 6 hours, and antihistamines can help.
11. Ciguatera Poisoning
This occurs after eating reef fish such as grouper or snapper that have fed on certain types of marine algae.
Symptoms develop within 6 hours and may include:
Burning or painful tingling in the arms or legs
Headache
Nausea and vomiting
Diarrhea
Hallucinations
Reversed temperature sensation (cold objects feel hot and hot objects feel cold)
There is no cure for ciguatera poisoning. While it usually resolves within days or weeks, neurological symptoms may persist for years.
12. Listeria Bacteria
Transmission Sources: Raw fruits and vegetables, dairy products, and meats.
Listeria causes a body-wide infection that is particularly dangerous for pregnant women and newborns.
It can contaminate fresh produce such as melons, as well as certain processed foods like cheese.
Symptoms — which typically appear 4 to 10 days after exposure — include fever, muscle aches, stomach upset, or diarrhea.
Prevention and Safety:
Wash and dry produce before eating.
Refrigerate foods below 40 °F.
Avoid unpasteurized soft cheeses, hot dogs, and deli meats.
Unpasteurized Dairy Products
Products made from raw milk, including yogurt and soft cheeses, can contain Listeria.
Because Listeria can survive cold temperatures, refrigeration does not kill it.
The elderly, pregnant women, and immunocompromised individuals are at highest risk.
Prevention and Safety: Always check for a label indicating the product is pasteurized.
Meats and Hot Dogs
Listeria can contaminate food processing plants and survive for years.
Heat kills Listeria, but contamination can occur after cooking if food touches surfaces that had raw meat.
Prevention:
Avoid pre-cooked or ready-to-eat foods.
Reheat hot dogs and meats until steaming hot (165 °F) before eating.
When to Call a Doctor
Most foodborne illnesses resolve on their own, but you should contact a doctor if you experience:
High fever
Bloody stools
Persistent vomiting
Diarrhea lasting more than 3 days
Signs of dehydration (dry mouth, dizziness, reduced urination)
General Tips for Protecting Against Food Poisoning
Wash your hands thoroughly before handling food.
Clean surfaces and utensils after contact with raw meat.
Wash food under running water and dry with paper towels.
Discard outer leaves of lettuce or cabbage.
Cook meat, poultry, and eggs at the proper temperatures.
In Conclusion : Certain groups face a higher risk of severe food poisoning, including pregnant women, the elderly, young children, and people with weakened immune systems.
These groups should avoid raw or undercooked meat and eggs, unpasteurized dairy products, raw seafood, and cold cuts.
If you suspect food poisoning, go to the hospital immediately and consult a doctor for the necessary tests.
