Listeriosis is a foodborne illness that can be very dangerous during pregnancy. Although rare, a Listeria infection in pregnancy can cause a range of problems, including miscarriage, premature birth and serious health problems for the baby.

“While listeria rarely causes severe illness in healthy adults, due to serious complications that can affect pregnancy, women should avoid foods at high risk of contamination and be alert to reports of outbreaks and food recalls,” says Shannon Smith, Ph.D. an ob/gyn at Brigham Faulkner Ob/gyn Associates and a member of the BabyCenter Medical Advisory Board.

To avoid listeria and other germs that cause food poisoning during pregnancy, skip deli meats and cheeses (unless steamed) and unpasteurized dairy products and juices. Thoroughly cook meat, poultry, fish and eggs. Store food at low temperatures and do not keep it too long before eating it. When preparing food at home, be sure to wash your hands, cooking surfaces and utensils thoroughly in hot, soapy water.

What is listeriosis?

Listeriosis is a serious infection you can get from eating food contaminated with the bacteria Listeria monocytogenes.

Pregnant women and their developing babies – as well as newborns, people with weakened immune systems and the elderly – are particularly vulnerable Listeria infection. In fact, pregnant women are 10 times more likely to contract listeriosis. Latin American pregnant women face an even greater risk and are 24 times more likely to contract listeriosis.

The primary threat to a pregnant woman is the devastating effect listeriosis can have on her pregnancy and baby.

The Centers for Disease Control and Prevention (CDC) estimates that about 1,600 people contract listeriosis in the United States each year. Approximately one-sixth of the reported cases occur in pregnant women.

Listeriosis symptoms

Listeriosis symptoms may appear a week to a month after consuming contaminated food, or they may not appear for several months. Many pregnant women have no listeria symptoms or only mild flu-like symptoms if they become infected. Even without symptoms, you can pass the bacteria to your baby.

Symptoms of listeriosis may include:

Call your doctor right away if you have any symptoms of listeriosis.

How can listeriosis affect me and my baby?

Unless you have an underlying illness that affects your immune system, listeriosis is unlikely to seriously affect your health during pregnancy. (Some pregnant women who have listeriosis suffer from dehydration from vomiting and diarrhea – but this is uncommon.)

However, the infection can have serious consequences for your developing baby, especially if you don’t get treatment in time.

Listeria can infect the placenta, amniotic fluid and baby; can cause miscarriage or stillbirth. Infected babies who survive are likely to be born prematurely. Many will be born seriously ill or become ill soon after birth, with problems that can include blood infection, difficulty breathing, fever, skin sores, multiple organ lesions and central nervous system infections such as meningitis. Some infected babies will die or suffer long-term effects, such as intellectual disability; paralysis; attacks; blindness; or brain, kidney, or heart problems.

Pregnant women are 10 times more likely to contract listeriosis.

– American College of Obstetricians and Gynecologists

Some infants of infected mothers appear healthy at birth but show signs of infection, usually meningitis, a week or even several weeks after birth. This so-called “late listeriosis” can be the result of infection of the baby during delivery. (An infected woman may have the bacteria in her cervix, vagina, or gastrointestinal tract.)

Not all babies born to mothers infected with listeriosis while pregnant will have problems. If the mother is treated with antibiotics during pregnancy, the baby can avoid infection.

How is listeriosis treated?

Your doctor will give you a blood test to confirm that you have listeriosis. If it’s positive, you’ll be given IV antibiotics, which will treat your infection and can help protect your baby.

An ultrasound can check for problems and allow your care team to see how your baby is growing.

After birth, your baby will have a blood test to see if he is infected Listeria. If they are, they will also receive antibiotics.

How to avoid food poisoning during pregnancy

To avoid infection with Listeria and other foodborne bacteria and viruses, follow these guidelines when selecting, storing, and preparing food:

Avoid unsafe food

You can’t tell if food is hidden Listeria by sight or smell. Therefore, it is important for pregnant women to be aware of the foods that are most likely to be contaminated and to avoid them. Stay away from:

• Shares meat and cheese, unless you reheat them. Do not eat cold cuts or deli meats, deli cheeses, chilled pâtés or meat spreads, or chilled smoked or pickled fish unless they are cooked until they are steaming hot (say, on a pizza or in a hot sandwich). And even though the hot dogs are ready, be sure to cook them until they are steaming hot. Canned or shelf-stable products that do not need to be refrigerated should be good to eat.

• Cold smoked fish that is not shelf stable. It’s okay to eat canned and shelf-stable tuna, salmon, and other fish. But cold-smoked fish that is not shelf-stable (labeled “Refrigerate”) is not safe unless it is cooked (for example, in a pan). These items are often found at deli or seafood counters and may be labeled “new style,” “lox,” “kippered,” or “smoked.”

• Prepared salads and wraps. Stay away from prepared salads in delis and supermarkets, especially those containing eggs, chicken or seafood. (Even vegetable salads can contain listeria, still.) Also, skip the potato salad that isn’t on ice at the picnic and the meat that isn’t hot at the buffet. Unless you’re sure the food is safely prepared and has been sitting for less than two hours – one hour on a very hot day – it’s not worth the risk.

• Unpasteurized (raw) milk. This includes raw milk and raw milk cheeses. Do not eat soft cheese such as feta, brie or camembert; cheese with blue veins; or Mexican-style cheese such as queso blanco, queso fresco, or panela (queso panela), unless the label clearly states that it is made from pasteurized milk. Fresh cheese, ricotta, cream cheese, processed cheese (such as American), and hard cheese (such as cheddar and parmesan) are considered safe, as are cultured dairy products such as yogurt and buttermilk.

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• Unpasteurized juice. Almost all juice sold in the US is pasteurized, but check the labels to be sure. Freshly squeezed juice at smoothie bars and farmers’ markets must not be pasteurized (or labeled). If you are not sure whether a particular juice is pasteurized, skip it.

• Raw sprouts. The warm, moist conditions needed for sprouts to grow are also ideal for growth Listeria and other bacteria. If you eat sprouts, cook them well. Rinsing off the germs will not remove the bacteria.

• Cantaloupe that is old or not refrigerated. Leave the melon in the refrigerator and eat it within a week. Discard sliced ​​melon if it sits at room temperature for more than four hours.

Keep food safe

• Check the temperature in the fridge and freezer. To protect your food from contamination by various disease-causing organisms, make sure your refrigerator is set between 35 and 40 degrees Fahrenheit (F) and your freezer at or below freezing. Use a refrigerator thermometer to confirm the temperature.

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• Don’t keep food too long. Eat perishable and ready-to-eat foods as soon as possible after you buy them, especially after you open them – even if they haven’t passed their use-by date yet. This date applies to unopened products. Hot dogs should be stored in the refrigerator and eaten within a week if the package is opened and two weeks if unopened. Unopened packages of deli meats should be refrigerated and eaten within two weeks. Once the package is opened, eat it within three to five days.

Prepare food carefully

• Avoid contaminating ready-to-eat foods. Keep any potentially contaminated food (such as unwashed produce; uncooked meat, poultry, or seafood; hot dogs; and deli meats) separate from clean produce and from cooked and prepared foods. Use separate cutting boards, plates and utensils for produce and for raw meat, poultry, seafood and eggs.

• Wash all products. Wash or peel all fruits and vegetables thoroughly before eating them. Do not rinse meat, poultry or eggs.

• Cook all meat, poultry, fish and eggs thoroughly. Use a food thermometer to check the internal temperature of the meat. Most meat should reach a temperature of 165 degrees F (or 180 degrees F in the leg for whole poultry). If you are not checking the temperature of the meat, cook it until it is no longer pink in the center. The fish should be cooked until the flesh in the middle becomes opaque. Boil the eggs until the yolk is set. And don’t try the food before it’s ready.

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• Reheat leftovers thoroughly. Listeria contamination can occur after the food has already been cooked or processed. Bacteria can survive – and, unlike many bacteria, continue to grow – in the refrigerator. So reheat any precooked leftovers to 165 degrees F or until steaming hot. If using a microwave oven, cover the food to retain moisture and ensure safe, even heating. Allow food to sit for a few minutes after microwaving to finish cooking. You can use a clean food thermometer to make sure the reheated food has reached 165 degrees F.

Keep things clean

• Wash your hands. After touching raw food, changing a diaper, touching an animal, or using the bathroom, wash your hands with hot soapy water for at least 20 seconds.

• Wash surfaces and utensils. Use warm, soapy water to wash counters, cutting boards, dishes, utensils and sinks after contact with potentially contaminated food.

• Clean dishcloths and dishcloths regularly. Used dish cloths and kitchen towels can contain bacteria. Wash them regularly in hot water. Kitchen sponges are also potential sources of bacteria and are difficult to clean thoroughly. Putting them in the dishwasher or microwave only kills some of the bacteria, so if you use sponges, change them often.

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• Wash the fridge. A cold fridge is helpful but not safe: Listeria is a hardy organism that can survive and even continue to grow at low temperatures (albeit more slowly). Clean the refrigerator regularly – including the interior walls and shelves – with warm, soapy water. Use a mild liquid dishwashing detergent, rinse, then dry with a clean cloth.

Listeriosis is not the only concern when it comes to food safety during pregnancy. This guide to foods and drinks you should avoid during pregnancy will help you avoid food poisoning and other dangers.