Lunch meats, also widely known as cold cuts or deli meats, are generally advised against for consumption during pregnancy due to the risk of foodborne illness. These ready-to-eat products can harbor harmful bacteria, even when properly refrigerated, posing a unique threat to the developing fetus. The primary concern is a specific type of bacterium that can survive and multiply in cold temperatures, unlike most other common food pathogens. The guidance to avoid these foods is based on an infection that affects pregnant women disproportionately compared to the general population.
The Specific Risk: Listeria Monocytogenes
The pathogen of concern in unheated deli meat is the bacterium Listeria monocytogenes, which causes an infection called listeriosis. Pregnant individuals are 10 to 20 times more likely to contract listeriosis than the general public. This heightened vulnerability is due to the natural suppression of the mother’s immune system during gestation.
The body achieves this immune shift by decreasing cell-mediated immunity, which relies on T-cells to defend against intracellular pathogens like Listeria. This immunological adaptation prevents the mother’s body from rejecting the fetus but makes it less capable of clearing the bacteria. While the mother’s symptoms are often mild and resemble the flu, the consequences for the fetus can be severe.
Once the bacteria infect the mother, they have an affinity for the placenta and can cross the placental barrier. Infection in the first trimester carries a miscarriage risk as high as 65%. Infection later in the pregnancy is associated with a fetal demise risk of around 26%. Listeriosis can also result in serious adverse outcomes such as stillbirth, premature birth, and severe neonatal infections including meningitis and sepsis. The mortality rate for the newborn can be as high as 20% to 30%, underscoring the seriousness of this food safety risk.
Sources of Contamination in Deli Products
Deli meats are vulnerable to Listeria contamination because they are ready-to-eat (RTE) foods that are not typically heated before serving. The bacteria are widespread in the environment, found in water, soil, and food processing facilities. Contamination often occurs after the meat has been cooked or smoked, known as post-processing contamination.
Recontamination happens when the meat contacts surfaces, such as slicers or packaging equipment, that have not been adequately sanitized. Listeria monocytogenes can survive and multiply at typical refrigerator temperatures of 40°F (4°C) or colder. Unlike most other foodborne pathogens, Listeria actively uses refrigeration for proliferation, meaning the meat becomes more dangerous the longer it sits in the fridge.
Cross-contamination is a significant factor, especially at the deli counter where different products are sliced using the same equipment. If a slicer is used for a contaminated product and not thoroughly cleaned, the bacteria can spread easily. This environmental persistence is why the United States Department of Agriculture (USDA) enforces a zero-tolerance policy for Listeria in ready-to-eat foods.
Safe Consumption Guidelines and Alternatives
Despite the recommendation to avoid cold cuts, deli meats can be made safe for pregnant individuals through proper heat treatment. The bacteria are destroyed when the meat reaches a specific high temperature. The Centers for Disease Control and Prevention (CDC) advises heating all luncheon meats, cold cuts, or deli meats until they are “steaming hot”.
The meat must reach an internal temperature of at least 165°F (74°C) throughout, which is required to kill Listeria. When using a microwave, it is important to ensure the product is heated evenly, as microwaves can sometimes heat foods unevenly. After heating, the meat should be consumed immediately and not allowed to cool back down.
For those seeking sandwich options without the risk, several alternatives are naturally safer because they undergo a high-heat preservation process or are cooked fresh. Canned products, such as chicken, tuna, or ham, are safe options because the canning process involves sufficient heat to eliminate the bacteria. Freshly cooked meats, like a chicken breast or roast beef cooked thoroughly at home and served immediately, also present no Listeria risk.
Other safe options include shelf-stable processed meats like jerky or pepperoni, which are not refrigerated and are processed differently. Proper handling of all foods, including keeping the refrigerator temperature at 40°F or lower and avoiding cross-contamination, remains an important safety measure. Following these heating instructions and choosing safe substitutes allows pregnant individuals to enjoy a variety of foods while minimizing the risk of listeriosis.