Pregnancy involves careful attention to diet, as certain foods carry risks that can affect both maternal and fetal health. Among the dietary concerns, dairy products, particularly mold-ripened varieties like blue cheese, often raise questions about safety. The soft structure of these cheeses can sometimes harbor harmful bacteria.
Understanding Listeria and Soft Cheeses
The primary concern with blue cheese and other soft, mold-ripened varieties is the potential presence of Listeria monocytogenes, a bacterium that causes the infection listeriosis. Pregnant individuals are particularly susceptible, being approximately 13 to 20 times more likely to contract listeriosis than the general population due to a natural suppression of the immune system during pregnancy. This bacterium thrives in environments that are high in moisture and low in acidity, conditions characteristic of many soft cheeses.
The consequences of listeriosis during pregnancy can be severe, as the bacteria can cross the placenta. While the pregnant person may only experience mild, flu-like symptoms, the infection poses a significant threat to the fetus. This can lead to serious complications, including miscarriage, stillbirth, premature birth, or severe illness in the newborn.
The Limitations of Pasteurization
Many consumers look for the “pasteurized” label, believing it eliminates the risk entirely. This process involves heating the milk to a temperature, such as 161°F (71.7°C) for 15 seconds, which kills any pathogens, including Listeria, that may have been present. Therefore, blue cheese made from pasteurized milk is initially free of the bacteria.
The safety concern, however, arises from the possibility of post-pasteurization contamination. Listeria is widespread in the environment and can contaminate the cheese after the heating process, such as during the ripening, handling, or packaging phases in the manufacturing facility. The traditional process of “needling” the cheese to introduce mold spores can also create pathways for environmental bacteria to enter the cheese interior.
Furthermore, the mold used in blue cheese production, Penicillium roqueforti, can increase the cheese’s pH level as it ripens. This change makes the cheese a more favorable environment for any Listeria that may have contaminated the product after pasteurization. Since Listeria monocytogenes can grow slowly even at standard refrigeration temperatures, the soft, less acidic nature of blue cheese remains a risk factor.
Safe Consumption Guidelines for Blue Cheese
Given the risk of post-pasteurization contamination, the general recommendation is to avoid eating any soft, mold-ripened cheese, including blue cheese, in its uncooked state. This guideline applies to varieties like Roquefort, Gorgonzola, and Danish Blue, even if the packaging confirms they were made with pasteurized milk. The safest method for consuming blue cheese during pregnancy is to ensure it is thoroughly heated.
The heat must be sufficient to destroy any potential Listeria bacteria present in the cheese. The accepted standard is to cook the cheese until it is visibly steaming hot all the way through, which typically means reaching an internal temperature of at least 158°F (70°C). Dishes like baked pasta, sauces, or pizza where the blue cheese is fully melted and bubbling are considered safe options.
When preparing food at home, it is also important to prevent cross-contamination by keeping uncooked blue cheese separate from other foods. Using different cutting boards and utensils for the cheese will minimize the risk of transferring bacteria to other ready-to-eat items. Adhering to these heating and handling guidelines ensures the enjoyment of the cheese without compromising maternal or fetal health.