5 Common Foods That Can Carry Parasites — Especially When They’re Raw or Undercooked

Parasites are not something most people think about when sitting down for a meal. Yet certain foods can carry microscopic organisms or parasite larvae when they are raw, undercooked, improperly handled, or contaminated during preparation.

This does not mean that these foods are inherently dangerous. In fact, many of them are nutritious and can be part of a healthy diet. The real concern is how they are sourced, stored, prepared, and cooked.

Fish and seafood are particularly important because some parasite species naturally occur in aquatic environments. Eating infected fish raw or insufficiently cooked can allow certain parasites to enter the digestive tract.

Here are five foods worth knowing about—and what you can do to reduce your risk.

1. Raw or Undercooked Salmon

Salmon is rich in high-quality protein and omega-3 fatty acids, making it a popular choice for a heart-healthy diet. However, raw or inadequately cooked salmon can carry parasites, depending on its species, origin, and processing.

One parasite of concern is Anisakis, a type of parasitic roundworm associated primarily with marine fish. Humans can become infected after eating raw or insufficiently cooked fish containing viable larvae.

In some cases, infection can cause abdominal pain, nausea, vomiting, diarrhea, or allergic-type reactions. Symptoms may develop relatively soon after eating contaminated fish.

This is why raw salmon served as sushi or sashimi should come from suppliers who follow appropriate parasite-control procedures.

Importantly, not every piece of salmon contains parasites, and properly prepared commercial seafood can be safe to eat raw when handled according to food-safety requirements.

If you're cooking salmon at home, thoroughly cooking it is one of the simplest ways to reduce parasite risk.

2. Raw Tuna and Other Marine Fish

Tuna is another extremely popular fish, especially in sushi, sashimi, poke bowls, and lightly seared dishes.

Like other marine fish, certain types of tuna can potentially harbor parasites. The risk depends on the species, geographic origin, handling, and whether appropriate parasite-control procedures have been used.

Eating fish raw creates a different food-safety situation from eating it fully cooked.

Cooking fish thoroughly is one of the most reliable ways to kill many parasites.

Freezing under appropriate conditions can also destroy many parasites, which is why commercial seafood intended for raw consumption may undergo specific freezing procedures.

However, consumers should not assume that ordinary household freezing automatically makes every raw fish product safe. Freezer temperatures and freezing duration matter, and freezing does not necessarily eliminate every possible foodborne hazard.

If you're preparing sushi at home, purchasing seafood specifically intended and handled for raw consumption is much safer than simply taking an ordinary piece of fish and eating it raw.

3. Freshwater Fish

Freshwater fish deserve special attention because several parasite species are associated with freshwater environments.

Examples include certain flukes, tapeworms, and other parasitic organisms that can infect fish. In areas where raw or lightly cooked freshwater fish are traditionally consumed, foodborne parasitic infections may be a greater concern.

Eating freshwater fish raw, pickled, salted, or only lightly cooked may not reliably kill parasites.

Some infections can cause digestive symptoms, while others may affect the liver or bile ducts depending on the particular parasite.

That is why proper cooking is especially important for freshwater fish.

If you enjoy dishes made with raw or fermented freshwater fish, don't assume that acidity, alcohol, salt, or traditional preparation methods necessarily destroy all parasites.

The safest approach is to follow established food-safety guidance for the specific dish and fish species.

4. Raw or Undercooked Squid and Other Seafood

Squid and other seafood can also be associated with parasites when consumed raw or inadequately cooked.

This is particularly relevant to dishes such as raw squid, lightly cooked seafood, and certain traditional preparations.

Parasites are only one part of the equation. Raw seafood can also carry bacteria and viruses, depending on contamination and handling conditions.

That means "parasite-free" does not automatically mean "risk-free."

Proper refrigeration, avoiding cross-contamination, and cooking seafood appropriately all matter.

When preparing squid at home, make sure it is handled hygienically and cooked thoroughly rather than relying on visual appearance alone.

For restaurant meals, choose reputable establishments that maintain appropriate seafood storage and preparation standards.

5. Raw or Undercooked Pork and Wild Game

Fish isn't the only food category that can carry parasites.

Raw or undercooked pork and certain wild game meats can also pose parasitic risks.

One well-known example is Trichinella, a parasitic roundworm that can infect people who eat meat containing viable larvae. Historically, infections have been associated with undercooked pork, although modern commercial pork production has significantly reduced the risk in many countries.

Wild game can present a different level of risk because animals such as wild boar may acquire parasites naturally.

Symptoms of trichinellosis can initially resemble a gastrointestinal illness, including nausea, diarrhea, abdominal discomfort, and vomiting. Later, some people can develop fever, muscle pain, weakness, or swelling around the eyes.

The simplest prevention strategy is straightforward:

Cook pork and wild game thoroughly according to appropriate food-safety recommendations.

Do not rely on the meat looking "mostly cooked" from the outside.

Why Raw Food Doesn't Always Mean Dangerous Food

Seeing the word "parasite" can make a food look frightening, but context matters.

Millions of people eat fish and seafood regularly without developing parasitic infections. Modern food-safety systems, commercial processing, proper refrigeration, parasite-control procedures, and cooking significantly reduce risk.

The problem is that raw or undercooked preparation can remove one of the most effective barriers against parasites: heat.

That's why raw seafood requires more careful sourcing and handling than fully cooked seafood.

It is also worth remembering that the images often used in viral social-media posts can be misleading. A photograph of a parasite does not prove that the food shown in the same picture contains that parasite.

Likewise, a food being "common" does not mean that it is "full of parasites."

The actual risk depends on the food, species, source, preparation method, and food-safety controls.

How to Reduce Your Risk

Fortunately, protecting yourself does not require eliminating fish or meat from your diet.

A few practical habits can make a major difference.

Cook seafood and meat properly

Heat is one of the most effective methods for destroying many foodborne parasites.

Use a food thermometer when appropriate rather than relying only on color or texture.

Be careful with raw seafood

If you eat sushi, sashimi, or other raw seafood, choose reputable restaurants and suppliers that follow established food-safety practices.

Don't assume marinating kills parasites

Lemon juice, vinegar, salt, alcohol, and other marinades may change the texture and flavor of seafood, but they should not automatically be considered a reliable substitute for proper cooking or validated parasite-control procedures.

Prevent cross-contamination

Keep raw fish and meat separate from ready-to-eat foods. Wash hands, utensils, cutting boards, and work surfaces appropriately after handling raw animal products.

Follow storage instructions

Seafood and meat are highly perishable. Keep them refrigerated or frozen as recommended, and avoid leaving them at unsafe temperatures for extended periods.

What If You Think You Ate Contaminated Food?

Don't panic.

Eating raw fish or undercooked meat does not automatically mean you have a parasitic infection.

However, if you develop persistent gastrointestinal symptoms, severe abdominal pain, unexplained fever, unusual muscle pain, or other concerning symptoms after eating potentially contaminated food, contact a healthcare professional.

Tell them what you ate, particularly if you consumed raw fish, undercooked meat, wild game, or seafood from an uncertain source. That information can help guide evaluation and testing.

Do not take antiparasitic medication simply because you saw a frightening parasite image online. Treatment depends on the specific organism and diagnosis.

The Bottom Line

Salmon, tuna and other marine fish, freshwater fish, squid and other seafood, and undercooked pork or wild game can potentially carry parasites under certain circumstances.

But this does not mean these foods are inherently unsafe or that people should avoid them altogether.

The biggest concern is generally raw or inadequately cooked animal foods, particularly when sourcing and food handling are uncertain.

Fish remains an excellent source of protein and important nutrients, including omega-3 fatty acids. The goal isn't to fear food—it's to prepare it safely.

So the next time you see a dramatic post claiming that a particular food is "packed with parasites," take a second before believing it.

The preparation method matters. The source matters. The species matters. And proper cooking and food handling matter most.

A healthy diet doesn't require paranoia about parasites. It requires good food-safety habits, informed choices, and a little common sense in the kitchen.