If you’re pregnant or planning to become pregnant soon, you may have heard all kinds of advice on what you should or shouldn’t eat during pregnancy. How do you know which foods to avoid during pregnancy based on medical research and what’s just an outdated bit of folk wisdom? Here are some facts about foods that should be avoided during pregnancy according to the Mayo Clinic.

1. Certain Seafood

You don’t have to avoid all seafood entirely during pregnancy, but you should be aware of seafood that’s high in mercury. The U.S. Food and Drug Administration (FDA) recommends avoiding the following species of fish during pregnancy:

• King mackerel
• Shark
• Swordfish
• Tilefish

For other types of seafood, you will probably be safe eating no more than 8-12 ounces per week. These types of seafood include:

• Anchovies
• Catfish
• Cod
• Light Canned Tuna
• Pollock
• Tilapia
• Trout

When eating seafood, make sure that it is fully cooked, because raw and undercooked seafood pose a risk of bacterial and viral contamination that can give you food poisoning. High levels of mercury are unsafe to eat during pregnancy because, according to the March of Dimes, babies exposed to mercury in the womb are at risk for brain damage, hearing problems, and vision problems.

2. Undercooked Eggs, Poultry, and Meat

Eating rare meat and undercooked chicken, turkey, duck, or eggs poses a risk like that of undercooked and raw seafood. Namely, these foods may contain bacteria that could give you food poisoning. Hot dogs and lunch meats should also be cooked until steaming hot or else avoided because of the rare but serious possibility of listeriotic contamination.

Be aware that some foods, such as Caesar dressing and eggnog, call for uncooked eggs as an ingredient. If you’re unsure of the ingredients of any homemade or restaurant food product, don’t be afraid to ask.

While it is rare for cases of bacterial food poisoning to affect babies in the womb, you may have a more severe reaction to bacterial food poisoning while pregnant than you would before and after pregnancy. Unwashed raw fruits and vegetables should also be avoided to reduce the risk of bacterial food poisoning.

3. Unpasteurized Foods

Most dairy products, such as milk and cheeses, are sold pasteurized to prevent the risk of bacterial contamination. However, certain kinds of products can be sold without this added layer of safety. They include unpasteurized juices, unpasteurized milk, and soft cheeses such as bleu cheese, Brie, and feta. If a juice, milk, or cheese product is clearly labeled as pasteurized, then it is safe to eat during pregnancy.

4. Herbal Tea

Many people are aware that alcohol should be avoided during pregnancy due to the risk of serious complications known as fetal alcohol syndrome and that excessive amounts of caffeine are still being studied as a potential risk factor for developing babies. Did you know that herbal tea should also be avoided during pregnancy?

Some kinds of herbal tea are specifically marketed for pregnancy, but since the effects of all the types of plants in herbal teas are unknown, it is best to avoid herbal teas unless you have asked your health care provider about a specific kind of herbal tea and gotten the okay to drink it during pregnancy.