Ask the Cheesehead: I'm lactose intolerant. Can I eat cheese?

One of the main processes involved in ripening cheese is the metabolism of lactose, as milk sugars are broken down into lactic acid. Most of the lactose found in cheese is removed with the whey during the production process. Ripened cheeses like cheddar and Swiss contain about 95% less lactose than whole milk and aged cheeses contain almost no lactose.

The amount of lactose retained in a cheese is directly related to the amount of moisture retained in it. Therefore, a cheese with a higher moisture content generally has a higher amount of residual lactose, although with many cheeses, including cheddar, the residual lactose will be fermented by the starter culture during cheese making.

A good way to know if there is any residual lactose in your cheese is to read the nutritional information on the label. If the amount of sugar is 0 grams, there's no lactose! You're good to go! If you're buying cheese at a market, ask the cheesemonger. But a general rule of thumb for people who are really sensitive is to stay away from fresh cheeses like ricotta, mozzarella and chevre and opt instead for aged, drier cheeses.