Is bologna safe to eat while pregnant? (Main risks)

In this brief guide, we will answer the question “Is bologna safe to eat while pregnant?”, and will discuss why bologna should be avoided by pregnant women and the dangers of Listeria infection.

Is bologna safe to eat while pregnant?

No, bologna is not recommended during pregnancy. Cold cuts, including bologna, are typically consumed without reheating, placing consumers at ongoing risk of exposure to zoonotic pathogens.

Of particular concern is the presence of Listeria monocytogenes. It is widespread and can grow under refrigerated conditions, especially in vacuum or strained atmosphere packaged cured meat products. (1)

Listeria monocytogenes is a Gram-positive bacterium found intracellularly and can thrive in both aerobic and facultative anaerobic conditions. Consumption of contaminated food is a common route of transmission and is responsible for the onset and development of the disease known as listeriosis.

Pregnancy-related listeriosis has an estimated incidence of 3 cases per 100,000 live births, with reported cases ranging from 1 to 25 per 100,000 live births, accounting for up to 35% of all Listeria infections. Interestingly, when this infection affects newborns, about half do not show any obvious immune problems. (2)

Why is Listeria dangerous to pregnant women?

Listeria has a propensity to disproportionately affect individuals with weakened immune systems, the elderly, pregnant women, and newborns. Notably, pregnant women are approximately 18 times more susceptible to infection compared to the general population.

This increased risk is attributed to the specific suppression of cell-mediated immunity during pregnancy and the tendency of Listeria monocytogenes to target the placenta. Once it enters the bloodstream, Listeria bacteria can disseminate to various body sites, with a preference for the central nervous system and the placenta.

The fetus is especially vulnerable to L. monocytogenes infection, which can result in adverse outcomes such as miscarriage, stillbirth, neonatal infection, and subsequent health complications after birth. (2, 3)

How can bologna get contaminated?

The slicing process has been identified as a significant source of both saprophytic and pathogenic bacterial contamination. Bologna, being an emulsion-type, non-fermented sausage, undergoes cooking, curing, and smoking during its manufacturing process to reduce the bacterial population. Nevertheless, it is commonly available in the market as pre-sliced, vacuum-packaged luncheon meat.

The microbial composition of vacuum-packaged luncheon meats undergoes alterations over time during storage. Typically, the majority of bacteria present on newly packaged products perish during storage, with lactic acid bacteria often becoming the dominant population within two weeks. (4)

What factors affect bologna contamination?

In my perspective as a food scientist, vacuum-sealed meat products such as bologna often yield inconsistent results in terms of pathogen growth, which can be attributed to various factors.

These factors include the temperature at which the packages are incubated, the presence or absence of competing microorganisms, the availability of oxygen influenced by the type of packaging film, and variations in intrinsic factors such as pH, water activity, and oxidation-reduction potential. These factors collectively impact the composition of microorganisms within the packaging.

At lower temperatures, typically in the range of 4-10°C, pathogenic bacteria like Staphylococcus aureus, Bacillus cereus, Clostridium perfringens, and Salmonella tend not to proliferate.

This observation is based on several inoculation studies involving the introduction of pathogens into naturally contaminated vacuum-sealed packages. Additionally, the initial level of pathogens in the packages often plays a crucial role in determining the potential for their growth. (5)

What other reasons should pregnant women avoid bologna?

Current nutritional recommendations and dietary guidelines encourage pregnant women to avoid the consumption of several meat products based on their nutritional profile. In most instances, meat products, such as bologna, share common characteristics, including a relatively high salt content, animal fat, and the presence of curing salts like nitrites and nitrates.

Bologna, in particular, is notable for its elevated animal fat content, typically ranging from 20-30%, resulting in a higher concentration of saturated fatty acids. Various studies established a link between excessive consumption of these components and the increased risk of cardiovascular diseases, certain types of cancer, and obesity. (6, 7)

How to avoid Listeria infections?

To reduce the risk of L. monocytogenes infection, pregnant women are recommended to follow safe food handling practices. This includes storing all perishable foods between 1.7 and 4.4 °C and promptly using refrigerated ready-to-eat foods. If a potentially hazardous perishable food cannot be consumed within four days, it’s advisable to freeze it or dispose of it.

Pregnant women are advised to steer clear of certain food items, including soft cheeses made with raw or unpasteurized milk, uncooked foods prepared with raw milk, raw or undercooked seafood, refrigerated smoked or precooked seafood, deli seafood salads, and items like hot dogs, luncheon meats, including bologna, and pâté.

These should only be consumed if reheated until steaming hot before serving or if they have been reformulated to eliminate the risk of Listeria. Leftover foods should be reheated to a temperature of 73.9 °C before consumption. (3)

What are the symptoms of Listeria infections?

Listeriosis often manifests as a mild flu-like illness, with symptoms like muscle aches, general discomfort, or fever. It may also manifest with urinary symptoms or uterine contractions. In the context of pregnancy, Listeriosis has been linked to adverse outcomes such as spontaneous abortion, stillbirth, premature delivery, and neonatal infections.

Gastrointestinal symptoms may appear within 2 to 3 days after exposure. If the body is unable to naturally clear the pathogen, and the infection becomes invasive, symptoms like fever, chills, headache, muscle aches, and backaches may develop, typically within 11 to 70 days after exposure. The prognosis is generally less favorable for fetuses affected at earlier gestational stages. (3, 8)

Conclusion

In this brief guide, we answered the question “Is bologna safe to eat while pregnant?”, and discussed why bologna should be avoided by pregnant women and the dangers of Listeria infection.

From my perspective as a food scientist, bologna is a very unhealthy food product, with high amounts of fat and salt, and carries the risk of listeria infections. For those reasons, it should be avoided by pregnant women.

References