Milk, yogurt, cheese and other dairy foods: composition, varieties, processing, storage and quality.
A2 milk is selected to contain A2 rather than A1 beta-casein. It is still cow's milk: lactose, total protein, calcium, fat, and calories are broadly similar to comparable regular milk. Some human studies report digestive differences, but A2 milk is not a treatment for lactose intolerance or milk allergy.
Ultrafiltration passes milk through membranes that retain protein and fat while allowing some water, lactose, and minerals through. By recombining those fractions, manufacturers can make milk with about 13 grams of protein per cup instead of the roughly 8 grams in regular milk.
Plain skyr usually stands out for protein, often around 10–11 g per 100 g. Plain yogurt and milk kefir are commonly closer to 3–5 g per 100 g. Fat, sugar, and calcium vary enough by brand that the Nutrition Facts panel still matters.
USDA lists about 1–2 weeks as a general refrigerated range for yogurt at 40°F (4°C) or below. Once opened, follow the manufacturer’s directions and use it sooner when practical. A little whey on top can be normal; mold, a swollen container, unexpected gas, or a clearly abnormal odor are not.
For protein concentration, Greek yogurt usually wins by a wide margin. USDA lists plain whole-milk Greek yogurt at about 9 g protein per 100 g, while many plain milk kefirs land around 3–4 g per 100 g. Kefir is thinner and drinkable, and traditional kefir fermentation includes a community of lactic-acid bacteria and yeasts rather than classic yogurt cultures alone.
Plain yogurt is a useful source of protein and calcium, but there is no single nutrition profile for all yogurt. Conventional plain yogurt often provides roughly 3–5 g protein per 100 g, while Greek yogurt can reach about 8–10 g; fat depends mainly on whether the starting milk is whole, reduced-fat or nonfat.
Fortified unsweetened soy milk can come very close to cow's milk in protein and calcium. A cup of 2% dairy milk provides roughly 8 g protein and 290 mg calcium; the FDA's fortified plant-beverage example provides 7 g and 300 mg. Soy is typically lower in saturated fat and contains no lactose, but calcium and vitamin levels depend on fortification.
Yes, cheese can be frozen, but quality depends heavily on the style. Hard and semi-hard cheeses generally tolerate freezing better, while soft and high-moisture cheeses may separate or turn grainy. Freeze tightly wrapped portions and thaw in the refrigerator with the final use in mind.
Most rinds created during ripening — natural rinds, bloomy rinds such as Brie and washed rinds — are edible. Wax, paraffin, plastic, plasticoat and other artificial coatings should be removed. When the surface is ambiguous, the package label is the best guide.
Opened cheese should go back into the refrigerator protected from drying and contamination. Hard cheese keeps best when wrapped without trapping heavy condensation; soft and fresh cheese should stay covered and be used sooner. The cheese type matters as much as the date you opened it.
Cheese does not melt well simply because it contains fat. Smooth melting needs a casein network that can soften without breaking, enough moisture, and the right balance of acidity and calcium. Age matters too: younger cheeses are usually more fluid and stretchy than very dry, long-aged cheeses.
Roquefort, Parmesan and feta are among the most sodium-dense cheeses. USDA references put Roquefort and grated Parmesan near 1,800 mg sodium per 100 g, while some mozzarella and Swiss cheeses are far lower. Actual serving size and the specific brand determine how much sodium reaches the plate.