Foodborne illness outbreaks are not random events. Rather, they are often linked to specific foods that have common contamination risks due to how they are produced, processed, stored, or prepared. While nearly any food can potentially carry pathogens, certain categories consistently top the list in food safety reports. Understanding which foods are most frequently implicated in outbreaks, and the reasons why, can help consumers make informed decisions and practice safer food handling habits.
1. Leafy Greens and Raw Produce
Leafy greens like romaine lettuce, spinach, and kale are frequently associated with outbreaks, especially those involving E. coli and Salmonella. The main reason for this is that these vegetables are often consumed raw, meaning there’s no heat step to kill pathogens.
Contamination can occur at many stages, including during growing (through contaminated water or animal feces), harvesting, or packaging. For instance, the 2018 multistate E. coli outbreak linked to romaine lettuce sickened over 200 people, prompting massive recalls and raising public awareness about produce safety.
Why the risk is high: No cooking step, high surface area for bacteria to cling to, and potential for cross-contamination during processing.
2. Poultry
Raw chicken and turkey are significant sources of Salmonella and Campylobacter. Despite regulations and safety measures in commercial poultry production, contamination still occurs regularly. The CDC notes that nearly 1 in every 25 packages of chicken at the grocery store is contaminated with Salmonella.
The problem doesn’t end there. Improper handling or undercooking in home kitchens and restaurants can cause these pathogens to spread. Using the same cutting board or utensils for vegetables after prepping raw chicken, or not cooking poultry to the recommended internal temperature of 165°F (74°C), are common mistakes.
Why the risk is high: Naturally occurring pathogens in raw meat, frequent undercooking, and cross-contamination in kitchens.
3. Ground Beef
Ground beef is another food commonly linked to foodborne illness, primarily due to E. coli O157:H7. When meat is ground, bacteria present on the surface can be mixed throughout the product, increasing the risk that undercooked burgers may carry live pathogens.
The 1993 Jack in the Box outbreak remains one of the most infamous foodborne illness cases in the U.S., leading to stricter federal meat inspection laws and the formation of modern food safety systems. That outbreak killed four children and sickened over 700 people due to undercooked burgers.
Why the risk is high: Grinding spreads bacteria internally; often cooked rare or medium-rare, especially in restaurants.
4. Dairy Products (Especially Unpasteurized)
While most commercial dairy products in the U.S. are pasteurized (heated to kill pathogens), outbreaks continue to be linked to raw milk, cheese, and ice cream products. Listeria monocytogenes is a major concern, particularly in soft cheeses like queso fresco.
In 2024, a large Listeria outbreak tied to deli meats and cheeses caused multiple deaths and hospitalizations, again highlighting the risks. Pregnant women, older adults, and immunocompromised individuals are particularly vulnerable.
Why the risk is high: Unpasteurized products can carry bacteria from the source, and Listeria can survive and multiply even in cold refrigeration.
5. Eggs
Raw or undercooked eggs have long been associated with Salmonella Enteritidis. Although the risk is significantly lower today due to improved production methods and testing, it’s not eliminated. Homemade mayonnaise, hollandaise sauce, or desserts like tiramisu that use raw eggs can still pose a threat.
In commercial baking or food service, pasteurized eggs are often used to reduce this risk, but consumers at home often use raw eggs without realizing the danger.
Why the risk is high: Bacteria can be inside the egg, not just on the shell; many people consume them raw or undercooked.
6. Shellfish
Oysters and other filter-feeding shellfish can accumulate harmful bacteria and viruses from contaminated water. Vibrio and norovirus are the two most common culprits in shellfish-related outbreaks. Unlike some bacteria, Vibrio is naturally present in marine environments and is not a result of pollution.
Eating raw or undercooked shellfish, especially during the warmer months when bacteria proliferate, increases the risk. In 2023, several cases of Vibrio vulnificus infection were reported on the East Coast, with some resulting in amputations or death.
Why the risk is high: Raw consumption and environmental contamination; warm waters increase bacterial growth.
Staying Safe
While no food is 100% safe, understanding the reasons why certain foods are more prone to contamination helps mitigate risks. Key safety tips include:
- Wash produce thoroughly and avoid pre-cut greens unless consumed immediately.
- Always cook meat and poultry to recommended internal temperatures.
- Avoid unpasteurized dairy and juice, especially if pregnant or immunocompromised.
- Practice good kitchen hygiene: use separate cutting boards for meat and vegetables, wash hands often, and sanitize surfaces.
- Refrigerate leftovers promptly and reheat foods thoroughly.
Final Note
Outbreaks continue to remind us that the food supply chain is complex and vulnerable at many points, from farm to fork. Leafy greens, raw meats, eggs, dairy, and shellfish are some of the riskiest food categories, not because they’re inherently dangerous, but because of how they’re handled and consumed. Through better consumer education and stricter industry standards, the risk can be managed, if not eliminated entirely.
