Food Poisoning: Symptoms, Causes, and Treatment

What is Food Poisoning?

Food poisoning, also known as foodborne illness, is an illness caused by eating contaminated food. Infectious organisms — including bacteria, viruses, and parasites — or their toxins are the most common causes of food poisoning. These harmful organisms can contaminate food at any point during its processing or production, or even when it's being prepared in your home or a restaurant.

According to the Centers for Disease Control and Prevention (CDC), each year roughly 1 in 6 Americans (or 48 million people) get sick from contaminated food. Of these, 128,000 are hospitalized, and 3,000 die.

Common Causes

Food poisoning can be caused by a variety of microorganisms. Here are some of the most common causes:

• Salmonella: A type of bacteria commonly found in raw or undercooked meat, poultry, eggs, and egg products. It can also be found in unpasteurized milk and juice.
• Campylobacter: Another type of bacteria often found in raw or undercooked poultry, unpasteurized milk, and contaminated water.
• E. coli (Escherichia coli): Certain strains of this bacteria, such as E. coli O157:H7, can cause severe food poisoning. It's often found in undercooked beef, unpasteurized milk and juice, and contaminated raw fruits and vegetables.
• Listeria: This bacteria can grow at cold temperatures, making it a concern for refrigerated, ready-to-eat foods like deli meats and soft cheeses.
• Staphylococcus aureus: This bacteria produces a toxin that can cause food poisoning. It's often spread by food handlers and can be found in foods like salads, sandwiches, and dairy products.
• Norovirus: A highly contagious virus that can be spread through contaminated food, water, or surfaces. It's a common cause of foodborne illness outbreaks in restaurants and catered events.
• Hepatitis A: A virus that can be spread through contaminated food or water, or by an infected food handler.
• Shigella: A bacteria that can be spread through contaminated food or water, or by an infected food handler. It's often found in foods like salads, raw vegetables, and dairy products.
• Clostridium perfringens: A bacteria commonly found in raw meat and poultry. It can also be found in gravies, sauces, and other foods that are prepared in large quantities and kept warm for a long time.
• Parasites: Organisms like Giardia and Cryptosporidium can cause food poisoning. They're often found in contaminated water and can be spread through food prepared with that water.

For more information on these and other causes of food poisoning, visit the FDA's Bad Bug Book.

Associated Symptoms

The symptoms of food poisoning can vary depending on the cause, but they often include:

• Nausea
• Vomiting
• Watery or bloody diarrhea
• Abdominal pain and cramps
• Fever
• Headache
• Muscle aches
• Fatigue
• Loss of appetite

Symptoms can range from mild to severe and can last from a few hours to several days. In some cases, food poisoning can lead to serious complications, such as dehydration, kidney failure, and even death.

When to See a Doctor

Most cases of food poisoning are mild and resolve on their own within a few days. However, you should seek medical attention if you experience any of the following:

• Frequent episodes of vomiting and inability to keep liquids down
• Bloody vomit or stools
• Diarrhea for more than three days
• Extreme pain or severe abdominal cramping
• An oral temperature higher than 100.4°F (38°C)
• Signs or symptoms of dehydration — excessive thirst, dry mouth, little or no urination, severe weakness, dizziness, or lightheadedness
• Neurological symptoms such as blurry vision, muscle weakness, and tingling in the arms

If you're in a high-risk group — such as adults age 65 and older, pregnant women, infants, and people with chronic diseases or weakened immune systems — it's especially important to see a doctor if you suspect food poisoning.

Diagnosis

To diagnose food poisoning, your doctor will likely perform a physical exam and ask about your symptoms, including when they started and what you've eaten recently. They may also ask about your work and travel history to determine if you've been exposed to any potential sources of contamination.

In some cases, your doctor may order diagnostic tests to identify the cause of your food poisoning and confirm the diagnosis. These tests may include:

• Stool tests: A sample of your stool may be sent to a laboratory to identify the infectious organism.
• Blood tests: A blood sample may be taken to check for certain bacteria or to assess your kidney function if you're severely dehydrated.
• Food tests: If the food you ate is still available, it may be tested for bacterial or viral contamination. This is more common during outbreaks when multiple people are affected.

For more information on diagnosing food poisoning, visit the Mayo Clinic.

Treatment Options

The treatment for food poisoning typically depends on the cause and the severity of your symptoms. In most cases, food poisoning resolves on its own within a few days. However, the following treatments can help alleviate symptoms and prevent complications:

Home Treatments

• Stay hydrated: Drink plenty of fluids to replace those lost through vomiting and diarrhea. Water, broths, and oral rehydration solutions (like Pedialyte) are good options. Avoid caffeine, alcohol, and sugary drinks, as they can worsen dehydration.
• Rest: Get plenty of rest to help your body recover.
• Eat bland foods: Once you're able to keep fluids down, try eating bland, low-fat, and easy-to-digest foods like toast, rice, bananas, and applesauce. Avoid dairy products, fatty foods, and spicy foods until you're feeling better.
• Over-the-counter medications: Medications like loperamide (Imodium) and bismuth subsalicylate (Pepto-Bismol) can help relieve diarrhea. However, these medications should not be used if you have bloody diarrhea or a high fever, as they can worsen certain types of food poisoning.

Medical Treatments

• Antibiotics: In some cases, your doctor may prescribe antibiotics to treat bacterial food poisoning. However, antibiotics are not effective against viral food poisoning and can sometimes worsen certain types of bacterial food poisoning.
• Intravenous (IV) fluids: If you're severely dehydrated, you may need to receive fluids through a vein in your arm. This is typically done in a hospital setting.
• Hospitalization: In severe cases, hospitalization may be necessary to monitor and treat complications.

For more information on treating food poisoning, visit the National Institutes of Health (NIH).

Prevention Tips

Preventing food poisoning involves practicing good food safety habits. Here are some tips to help reduce your risk:

• Wash your hands: Wash your hands thoroughly with soap and warm water before and after handling food, after using the bathroom, and after changing diapers.
• Clean surfaces and utensils: Wash cutting boards, dishes, utensils, and countertops with hot, soapy water after preparing each food item.
• Separate raw foods: Keep raw meat, poultry, seafood, and eggs separate from other foods in your grocery cart, refrigerator, and while preparing meals.
• Cook foods thoroughly: Use a food thermometer to ensure that foods are cooked to a safe internal temperature. This can kill harmful bacteria.
• Refrigerate promptly: Refrigerate or freeze perishable foods within two hours of purchasing or preparing them. If the room temperature is above 90°F (32°C), refrigerate within one hour.
• Defrost foods safely: Thaw frozen foods in the refrigerator, in cold water, or in the microwave. Never thaw foods at room temperature.
• Avoid risky foods: Be cautious with foods that are more likely to be contaminated, such as raw or undercooked meats, unpasteurized milk and juices, and raw sprouts.
• Be careful with leftovers: Reheat leftovers to at least 165°F (74°C) to kill any bacteria that may have grown. Discard any food that has been left out at room temperature for more than two hours.

For more food safety tips, visit the FoodSafety.gov website.

Emergency Warning Signs

Seek emergency medical care if you experience any of the following symptoms, as they may indicate a life-threatening condition:

• Difficulty breathing or swallowing
• Severe vomiting that persists for more than 24 hours
• Bloody vomit or stools
• Severe abdominal pain or cramping
• High fever (over 102°F or 38.9°C)
• Signs of severe dehydration, such as very dark urine, very little urine, rapid heartbeat, dizziness, or confusion
• Neurological symptoms, such as muscle weakness, tingling in the arms, or blurry vision
• Symptoms that improve but then return or worsen

If you or someone else is experiencing these symptoms, call 911 or go to the nearest emergency room immediately.

For more information on food poisoning and food safety, visit reputable sources like the CDC, World Health Organization (WHO), and Cleveland Clinic.