Although the variety in the dairy case is impressive, the steps you should take to protect yourself from most dairy-related foodborne illnesses are blessedly simple. Never drink unpasteurized milk, and skip cheese made from unpasteurized milk if you are immune-compromised.
Why? Cow’s milk can be contaminated with many of the same pathogens found in beef—E. coli, Salmonella, and Listeria are the big three. The bacteria get into the milk from the cow’s intestinal tract, from contact with the udder and other parts of the cow that may have microscopic traces of manure, and from mixing milk from multiple cows in a bulk milk tank (present on almost every dairy farm in America—even the small ones).
Fortunately, there’s an easy way to kill the bacteria in milk while preserving all of the key nutrients, like vitamin D and calcium: pasteurization. Any properly pasteurized milk that has been held at the correct temperature (refrigerated during transportation; in the dairy case; and, later, at home) should be safe to drink.
Because unpasteurized (raw) milk may harbor dangerous bacteria, most states ban its sale in grocery stores. Indeed, it is illegal under federal law to bring raw milk across state lines to sell it—and that’s good news. In some states, raw milk can be sold from the farm directly, under cow-share programs, or as pet food—these are all dangerous loopholes. Milk straight from the cow may taste a little different than pasteurized milk, but it is simply too unsafe to consume and provides no scientifically verifiable benefit that might justify the very real risk.
It’s tempting to believe that if you know the dairy farmer and the conditions in which the cows are raised and milked, you could have greater confidence in raw milk, but that’s magical thinking. No farmer, no matter how diligent or loving, and no cow, no matter how content or clean, can guarantee the safety of raw milk. You simply should steer clear and drink safe, pasteurized milk.
Organic pasteurized milk is another story. To earn a “USDA Organic” label (the only organic label you should rely on), milk must come from cows that have access to the outdoors; have not been given growth hormones, antibiotics, or other drugs; have eaten only 100 percent organic feed for at least a year; and have eaten at least 30 percent of their diet from pasture during the primary growing season.
Sound good? It is: choose organic dairy when you can to promote organic farming. But organic and conventional milk are essentially equal from a bacterial standpoint. So if organic milk is too pricey or is not available, conventional is certainly as safe and nutritious.
Milk is processed into a wide variety of yogurt, kefir, cottage cheese, sour cream, and other products. The yogurt shelves have exploded with an array that includes Greek, Icelandic, fruit-on-the-bottom, probiotic, and others, in an endless variety of fruit flavors (and honey, chocolate, and caramel).
As long as the milk from which it was made was pasteurized, the yogurt has been kept cold, and it has not expired, you can enjoy yogurt without worrying about bacterial contamination. That’s mostly true for cheese too.
Store shelves display a bounty of crumbly and block, sharp and mild, soy and lactose-free, and sliced and shredded cheese. The main safety measure is to avoid cheese made from raw milk if you are immune-compromised (including young children), pregnant, or an older consumer. The complication? It’s not unheard of for certain pasteurized cheeses (typically soft-ripened cheeses) to cause outbreaks as well.
Hard cheeses, such as cheddar, Swiss, and Parmesan, don’t pose a safety problem (but are high in saturated fat). Most of those cheeses are made with pasteurized milk, and if they aren’t, the low-moisture, high-sodium content, and low pH of the harder cheeses makes them a hostile environment for bacteria. If any bugs were in that cheese, it would be hard for them to grow.
Soft cheeses are another story. Whether they are made from pasteurized milk or raw milk (which is legal in cheese making, as long as the cheese is aged at least 60 days), soft cheeses are notorious for causing serious illness from Listeria. In soft cheese, the bug can grow and thrive even in refrigerated conditions and, worse still, can survive on the plastic packaging and contaminate other cheeses nearby in the grocery store.
If you are immune-compromised, elderly, or pregnant, we recommend avoiding soft cheeses, whether made from raw or pasteurized milk. For others, soft cheese should be safe, but pay attention to proper refrigeration and expiration dates at home.
Other relevant links:
• Common questions about food safety and pregnancy, answered. See: Food Safety during Pregnancy
• What you need to know about the deli counter. See: Food Safety at the Deli Counter
• Learn about some of the common bacteria, toxins, viruses, and parasites in food. See: What’s Bugging You? Check Out this Table of Potential Food Safety Risks.