Milk, yogurt, cheese and other dairy foods: composition, varieties, processing, storage and quality.
A very strong smell can be completely normal in ripened cheese. Microbes and enzymes generate volatile aroma molecules, including sulfur compounds that are noticeable at tiny concentrations. The key question is whether the smell fits the cheese style or is a new, abnormal change.
The round holes in Swiss-style cheese are gas bubbles that became part of the structure. Propionibacterium freudenreichii metabolizes lactate and produces CO₂; when the cheese matrix is elastic enough to hold that gas, the bubbles expand into the openings cheesemakers call eyes.
Cheese is made from milk, but it does not keep all of milk’s lactose. Roughly 98% of milk lactose is removed in whey or converted to lactic acid during cheesemaking, and residual lactose is metabolized early in ripening. Many firm aged cheeses therefore end up with very small amounts.
Cheese can “sweat” for several reasons. Temperature changes move water through the cheese and can create condensation; warming makes milk fat more fluid; and fresh high-moisture cheeses can release whey. A few clean droplets are a different finding from slime, off odors or unexpected mold.
Cottage cheese and ricotta look similar in a bowl but are structured differently. A 2% cottage product can provide much more protein for the same calories, while whole-milk ricotta brings more fat, richness and a smoother filling texture.
USDA whole-milk ricotta provides about 157 calories, 7.8 g protein and 11 g fat per 100 g. A whole-milk mozzarella reference is around 300 calories, 22 g protein and 22 g fat. Mozzarella is much more concentrated, although very fresh high-moisture mozzarella can be substantially lighter than that reference.
USDA references put whole-milk mozzarella near 300 calories, 22.2 g protein and 22.4 g fat per 100 g, versus roughly 403 calories, 24.9 g protein and 33.1 g fat for cheddar. Cheddar has only about 2.7 g more protein but roughly 11 g more fat per 100 g.
Hard Parmesan contains roughly 35–36 g protein per 100 g, more than ten times the concentration in milk. Aging does not create new protein: curd formation, pressing and months of moisture loss concentrate the casein and other milk solids that remain in the cheese.
Plain skyr can pack a large amount of protein into a small cup. Icelandic Provisions Plain Skyr currently provides 17 g protein, 120 calories, 2.5 g fat and 3 g sugar per 150 g—about 11.3 g protein and 80 calories per 100 g.
Skyr does not automatically beat Greek yogurt for protein. Normalized to 100 g, Icelandic Provisions Plain Skyr provides about 80 calories, 11.3 g protein and 1.7 g fat; FAGE Total 0% plain Greek yogurt works out to about 53 calories, 10.6 g protein and 0 g fat. Both are concentrated dairy foods; the specific fat level and recipe matter.
In equal 150 g servings, current labels are surprisingly close for energy: Icelandic Provisions Plain Skyr has 120 calories and 17 g protein; Good Culture 2% cottage cheese has 130 calories and 19 g protein. The bigger contrast is sodium: 55 mg in skyr versus 520 mg in cottage cheese.
Cottage cheese can deliver close to 20 g protein in one small cup. Good Culture 2% provides 19 g protein, 130 calories and 3 g fat per 150 g; its 4% whole-milk single serve also provides 19 g protein but 140 calories and 6 g fat. Sodium is often the number worth checking alongside protein.