If you’ve ever been hit with sudden nausea and an urgent need to stay near a bathroom, you know how miserable stomach troubles can be. But is it a virus or something you ate?  

Foodborne illnesses have been getting a ton of attention lately thanks to two very high-profile recent outbreaks. The outbreaks are high-profile because they were associated with two very popular brands and occurred within weeks of each other.

E. coli and McDonalds (October 2024): An E. coli outbreak was associated with McDonald’s Quarter Pounders across 13 states, resulting in dozens of hospitalizations and at least one death. It turned out that the cause of the outbreak was slivered onions used in Quarter Pounders and not the burger meat. But in the public consciousness, the outbreak will always be associated with McDonald’s because of its high-profile brand, the popularity of Quarter Pounders, and the fact that McDonald’s was able to help trace the cause of the outbreak back to Taylor Farms and its Colorado processing facility. 

Listeria Outbreak Linked to Boar’s Head Deli Meats (July-September 2024): If you were to ask people to name a brand of deli meat, Boar’s Head is likely the only name that would come to mind. So, it was particularly frightening when a large Listeria outbreak, resulting in at least 59 hospitalizations and ten deaths in 19 states, was traced back to Boar’s Head. It turned out to be the largest Listeria outbreak in more than a decade. Boar’s Head has permanently closed the contaminated Virginia plant, recalled seven million pounds of deli meat, and has completely discontinued the manufacturing of liverwurst, the first contaminated product. It’s hard to imagine how serious the outbreak could have been if more people actually ate liverwurst!  

But despite those recent high-profile outbreaks, the incidence of foodborne illnesses has not increased in recent years. The Centers for Disease Control and Prevention (CDC) estimates that each year, approximately 48 million people in the United States experience foodborne illnesses, leading to 128,000 hospitalizations and 3,000 deaths. Still, when you are sick to your stomach it is more likely to be a plain old stomach virus. Since stomach viruses can spread from surfaces, contaminated food, or person-to-person contact, they’re harder to control and more likely to affect large groups of people quickly. By contrast, foodborne illnesses typically require exposure to specific contaminated foods or poor handling practices, which limit their scale and frequency.

Viruses Are More Common, but Foodborne Illnesses (aka Food Poisoning) are More Deadly 

Stomach viruses, also known as viral gastroenteritis, spread easily from person to person through contaminated surfaces. You can pick them up anywhere. Unlike respiratory viruses which spread through droplets in the air, stomach viruses spread when viruses from fecal matter are deposited on shared surfaces or even on food. This is why restaurant “employees must wash hands before returning to work.”  

The most common member of the stomach virus family is norovirus. It’s the quickly spreading virus responsible for making cruise ships, schools, or any close quarters, a lot less fun. The norovirus is tricky—it’s a virus, but it can be spread through contaminated food like salad bars, where many people may be in contact with the same food areas. It is not considered a foodborne illness because the contamination comes from humans and not from the food itself. There are other stomach viruses, like the rotavirus and the astrovirus, but they all spread and are treated the same way and all present with similar symptoms. 

Foodborne illnesses are caused by bacteria (usually) or parasites lurking in contaminated food or water. Common culprits include Salmonella, E. coli, and Listeria. Unlike a stomach virus, which you catch from another person, foodborne illnesses come from foods that have been improperly handled, stored, or cooked. 

• Salmonella: Comes from raw eggs and undercooked poultry. 

• E. coli: Often comes from undercooked beef or contaminated veggies.  

• Listeria: Found in deli meats and unpasteurized cheeses. It’s dangerous, especially for pregnant women. 

• Parasites: Parasites are the type of foodborne illness that show up in raw or undercooked food and sometimes don’t leave for weeks. Toxoplasma gondii (undercooked meat), Trichinella (pork and wild game), and Anisakis (raw seafood) are the biggest culprits. Parasites are the least common type of foodborne illness but can be difficult to remedy. 

Symptoms: How to Tell the Difference 

Both stomach viruses and foodborne illnesses present with the following symptoms: 
nausea, vomiting, diarrhea, abdominal pain, headaches, muscle aches, and fever. So how can you possibly know whether you have a virus or a foodborne illness? 

It is a matter of degree (and a few other things)! 

• Both a virus and a foodborne illness can cause diarrhea. But if your diarrhea is bloody, you most likely have a foodborne illness. 

• A stomach virus may cause a low-grade fever and muscle aches. But if you have a fever higher than 101º and chills, you most likely have a foodborne illness. 

• A stomach virus may cause some abdominal pain. But if you have severe stomach cramps, you most likely have a foodborne illness. 

• When you have a stomach virus, your nausea and vomiting or diarrhea may appear suddenly and may resolve within 24-48 hours. But if your symptoms begin slowly and become increasingly severe, you most likely have a foodborne illness. As a matter of fact, full-blown symptoms of foodborne illnesses may take several days to develop after you have ingested the contaminated food. This is why it is sometimes difficult to trace the causes of these outbreaks. 

• Because foodborne illnesses may take longer to resolve, sufferers may become dangerously dehydrated. This can compound the problem and should be a cause of concern.  

When You Are Sick 

Mild to moderate cases of both stomach viruses and foodborne illnesses can resolve themselves if you rest and make sure to replace the vast quantities of fluid you are losing. Best practice is to drink fluids with electrolytes to replace those your body has lost. 

But some foodborne illnesses require medical intervention including antiparasitic drugs, antibiotics, and/or intravenous fluids and electrolytes. 

When to Seek Medical Help 

While many cases of foodborne illness clear up on their own with rest and hydration, prolonged or worsening symptoms will require medical attention. Also, if you have a foodborne illness, you may be part of an outbreak.  

• High fever (above 101.5°F) 

• Severe dehydration (dizziness, dark urine, dry mouth) 

• Persistent vomiting or bloody diarrhea 

• Symptoms lasting more than a week 

How to Prevent Foodborne Illness at Home 

• Clean: Wash hands, utensils, and surfaces often. Rinse fruits and vegetables under running water without soap or commercial produce washes.  

• Separate: Avoid cross-contamination by keeping raw meat, poultry, seafood, and eggs separate from ready-to-eat foods. Use separate cutting boards for meats and veggies, wash hands, and clean surfaces after handling raw foods. 

• Chill: Refrigerate perishable foods promptly and keep your refrigerator at or below 40°F to slow bacterial growth.  

• Cook: Bacteria love warmth. Use a food thermometer to ensure foods are cooked to safe internal temperatures. For example, cook poultry to 165°F and ground meats to 160°F.  

• Watch for recalls: Certain foods, like deli meats, pre-cut produce, or unpasteurized dairy, are more likely to harbor bacteria like Listeria. Check recalls and avoid at-risk foods if you’re pregnant, elderly, or immunocompromised. 

Reducing Risk of Foodborne Illness When Eating Out 

• Choose Restaurants with High Standards of Cleanliness 

• Check Health Ratings. Many cities require restaurants to display their health inspection scores or make them available online. Aim for places with high health ratings, as they’re more likely to follow safe food handling practices. 

• Observe Cleanliness. Look around when you enter. Clean floors, tables, and bathrooms can be indicators of a restaurant’s overall cleanliness and attention to hygiene. 

•  Avoid Higher-Risk Foods. Some foods are more prone to contamination and may carry higher risks when eaten outside of home: 

• Raw or undercooked eggs: Avoid dishes like Caesar dressing, steak tartare, or certain desserts that may contain raw eggs unless you’re confident the restaurant uses pasteurized eggs. 

• Undercooked meats and seafood: Steaks, sushi, or shellfish can harbor harmful bacteria if not properly cooked. Ordering meat “well-done” and ensuring seafood is fully cooked can reduce the risk. 

• Unwashed or uncooked produce: Salads, raw sprouts, and certain fruits can carry foodborne viruses if they haven’t been washed properly. 

• Observe Food Temperature and Preparation 

• Hot Foods Should Be Hot, Cold Foods Cold: Foods should be served at the right temperature, hot foods should be steaming, and cold foods should feel fresh from refrigeration. If your food isn’t the right temperature, it could be a sign that it’s been sitting out too long. 

• Buffets and Salad Bars: These can be risky, as food often sits out at room temperature. If you choose to eat at a buffet, look for places that regularly check and replace dishes, and skip items that are lukewarm or look like they’ve been sitting out for a while. 

• Use Caution with Leftovers 

• Get Them Home Quickly: Bacteria can multiply quickly at room temperature. If you plan to take leftovers, refrigerate them as soon as possible, ideally within 1-2 hours. 

• Reheat Thoroughly: When you reheat leftovers, make sure they’re steaming hot (165°F or more) to kill any potential bacteria. 

The Bottom Line on Stomach Viruses Versus Foodborne Illnesses 

The recent outbreaks of foodborne illnesses provide us with a good opportunity to learn to identify, handle, and prevent them. While stomach viruses are more common, foodborne illnesses are generally more severe and more preventable. At home, keep raw meat and poultry separate from any other food during the preparation process. Cook hot food well and keep cold food cold. When eating out, avoid risky food and risky restaurants.  

If you do get sick, get plenty of rest and make sure to replace your lost fluids and electrolytes. If your symptoms persist and get worse, contact a medical provider and be ready with information about your pre-illness food intake. Your bad luck and upset stomach could help identify the next high-profile outbreak!