Pregnancy often brings heightened attention to food safety, especially concerning soft cheeses like mozzarella. While many soft varieties are typically avoided due to potential bacterial risks, mozzarella is often an exception that requires a careful check of its preparation. The safety of enjoying this mild, stretchy cheese depends almost entirely on one specific manufacturing step. Determining whether a particular mozzarella product is safe involves understanding the process used to treat the milk from which it was made.
The Role of Pasteurization in Cheese Safety
Pregnant individuals are at a significantly higher risk of contracting listeriosis, a serious foodborne illness caused by the bacterium Listeria monocytogenes. This risk is elevated because the immune system is naturally suppressed during pregnancy. Listeriosis can have severe consequences for the developing fetus, including miscarriage, stillbirth, or severe illness in the newborn.
The primary defense against this organism in dairy products is pasteurization, a process where milk is heated to a high temperature for a specified period. This heat treatment effectively eliminates harmful pathogens, including Listeria monocytogenes, before the cheesemaking process begins. When cheese is made from unpasteurized or raw milk, the bacteria have a greater opportunity to survive and multiply, especially in soft, high-moisture environments. The safety of any soft cheese, including mozzarella, hinges on confirming that the milk source was pasteurized.
Navigating Different Types of Mozzarella
The different forms of mozzarella found in grocery stores have varying degrees of inherent safety, making careful label reading necessary. Low-moisture, part-skim mozzarella, such as the pre-shredded varieties commonly used on pizza, is almost universally made from pasteurized milk. The lower water content in this type also makes it a less favorable environment for bacterial growth compared to its fresh counterparts. This commercial, drier form of the cheese is generally considered safe to consume cold or cooked, provided it is a commercially packaged brand.
Fresh mozzarella, which is typically packed in water or brine, requires a more careful check because of its higher moisture content. When purchasing these soft balls of cheese, such as bocconcini or ciliegine, the label must explicitly state that the product was made with pasteurized milk. Imported varieties, like the traditional Mozzarella di Bufala made from water buffalo milk, are more likely to be unpasteurized or made with raw milk, so explicit pasteurization confirmation is especially important for these products.
A further layer of safety is added when mozzarella is cooked thoroughly, such as on a pizza or in lasagna. Heating the cheese until it is steaming hot, reaching an internal temperature of at least 165°F (75°C), will destroy any potential Listeria bacteria that might be present. If there is any doubt about the pasteurization status of a mozzarella product, cooking it until it is bubbling and hot renders it safe to consume.
Safe Handling and Storage Practices
Minimizing the risk of contamination extends beyond the initial purchase and includes proper handling in the home kitchen. All mozzarella, especially the fresh, high-moisture variety, should be stored promptly in a refrigerator maintained at or below 40°F (4°C). Storing the cheese at this temperature is important because it inhibits the growth of bacteria like Listeria, which can multiply even in refrigerated conditions, albeit slowly.
Fresh mozzarella, once the factory seal is broken, should be consumed within a few days, even if the overall expiration date is further out. Its high water content means it has a shorter shelf life than hard, aged cheeses, making it susceptible to post-processing contamination. Avoiding pre-packaged or deli-counter mozzarella that has been sitting in an open container for an unknown duration can prevent exposure to cross-contamination. Always use clean utensils when handling the cheese and discard any portion that has passed its expiration date or shows any signs of spoilage.