Feta cheese, a brined curd white cheese traditionally made from sheep’s milk or a blend with goat’s milk, is a popular food item that raises questions for expectant mothers. The quick answer is a conditional yes: consumption is safe only when the cheese has been produced using specific methods that eliminate a particular food safety risk. The primary concern is not the cheese itself, but the process of its creation, which determines if it harbors a harmful bacterium.
Understanding the Specific Health Risk
Feta cheese is flagged as a concern due to the risk of contamination with the bacterium Listeria monocytogenes. This microorganism causes Listeriosis, a severe foodborne illness that poses a significant danger to pregnant individuals and their fetuses. While a healthy adult may only experience mild, flu-like symptoms, the infection is far more serious during pregnancy. Pregnant women are 10 to 20 times more likely to contract Listeriosis than the general population due to immune system changes. The Listeria bacteria can cross the placenta, leading to systemic infection in the fetus even if the mother’s symptoms are mild. This invasive infection can result in devastating outcomes, including miscarriage, stillbirth, premature birth, or severe infection of the newborn.
The Critical Role of Pasteurization
Pasteurization is the primary way to mitigate the risk of Listeria monocytogenes in feta cheese. This process involves heating the milk to a specific temperature for a set period, which kills harmful bacteria. Feta made with properly pasteurized milk is considered safe for pregnant women. Expectant mothers must check the packaging label to confirm the feta was “made with pasteurized milk.” Most commercial feta sold in major grocery stores is pasteurized. Unpasteurized varieties, often called “raw milk” cheese, are typically found in imported, artisanal, or farmer’s market products and should be avoided. The moisture content and low acidity of soft cheeses like feta can allow Listeria to grow, even under refrigeration.
Cooking Feta to Ensure Safety
If the pasteurization status of feta is uncertain, or if it is a high-risk artisanal variety, heating provides a secondary layer of protection. Cooking the cheese to a sufficiently high temperature will destroy any present Listeria bacteria. The guideline is to heat the feta until it is steaming hot throughout, corresponding to an internal temperature of at least 165°F (74°C). This process makes feta safe when incorporated into dishes such as baked pasta, casseroles, or cooked dips. Ensure the cheese is truly hot all the way through, as a warm or partially melted piece may still harbor bacteria. Cooking is an effective method for safely enjoying soft cheeses when the source or production method is uncertain.
Other Soft Cheeses to Approach with Caution
The safety guidelines for feta extend to a broader category of soft and semi-soft cheeses. Any cheese with high moisture and low acidity carries a heightened risk of Listeria contamination if made with unpasteurized milk.
High-Risk Cheeses
- Brie
- Camembert
- Roquefort
- Queso Fresco
All mold-ripened or soft, unpasteurized cheeses should be avoided unless cooked until steaming hot. Hard cheeses, such as Cheddar and Parmesan, are safe because their lower moisture content inhibits bacterial growth. Pregnant individuals should apply the “check the label or cook it” rule to virtually all soft dairy products.