Lactose is a type of sugar found in milk. The Oxford Companion to Food defines lactose as “the main and almost the sole sugar in milk…composed of the simple sugars dextrose and galactose.” The Oxford Companion goes on to describe how lactose is digested: “Splitting lactose into these two sugars is the first stage in digesting it, and is done with the aid of the enzyme lactase.” (1)
As lactose ferments during the cheese making process, it is converted into lactic acid. When this occurs, the separation of curds from the whey begins. This happens naturally in raw milk; however, pasteurized milk does not contain the necessary bacteria to cause consistent fermentation. Most cheesemakers rely on starter cultures with bacteria to start and control the process. Most of the lactose washes away with the whey. The small amount left with the curds further dissipates as the cheese ages, usually within days.
Cheeses aged more than two weeks and not with a high salt content (e.g. feta) contain such an insignificant amount of lactose as to be considered “lactose-free”. Many cheese makers advertise their cheese as “Naturally Lactose-Free” including Oltermanni Baby Muenster from Finlandia and many of the Gouda-Style cheeses made by Beemster.
Because lactose is a sugar on the ingredient label check for the amount of sugar and if it lists it as “0”, then you can be assured that the cheese is indeed lactose-free.
There is no scientific evidence to suggest that one animal’s milk is easier to digest than another. For example, one cup of cow milk contains 11 grams of lactose and one cup of goat milk contains 9 grams of lactose.
Some people who believe they are lactose-intolerant may actually be allergic to milk; however, the term lactose-intolerant has gained so much popularity that many confuse the two conditions.