It is used in lacto-fermented beverages, vegetables, mayo... I don't even know of all the uses.
Lacto- fermentation preserves foods for long periods. The lactic acid produced from the starches and sugars in fruits and vegetables is a natural preservative that inhibits putrefying bacteria. The proliferation of lactobacilli in fermented foods enhances their digestibility and increases vitamin levels. This fermentation process has been used traditionally around the globe for many, many years. This was one of the first things that I learned to do on my real food path for healing and maintaining a healthy digestive system.
First, you need a good quality plain yogurt or you need to make your own from raw milk. Since I don't have access to local raw milk and haven't yet mail ordered any (expensive!), I purchase Brown Cow or Strauss plain yogurt.
Pour the desired amount of yogurt (1/2 a container usually produces 1/2 cup or a bit more of whey) into a lined strainer over a bowl and leave on the counter. I line my strainer with a linen towel. After a few hours you can suspend the towel over a cup or bowl without the strainer. I use a chopstick and large drinking cup. This holds 1/2 a container of yogurt easily, but would not accomodate a full quart of yogurt. I have seen others (Kelly the Kitchen Kop) hang larger amounts from a chandelier, over a bowl. Make use of what you've got!
Continue collecting the whey until it stops dripping. Sometimes I collect the whey for 12 hours and other times for longer. It really is up to you. When it stops dripping, you have collected all the available whey. Pour the collected whey into a small mason jar for storage in the fridge (about 6 months). You can also keep the yogurt "cheese" in the fridge (about 1 month) and use instead of cream cheese. I do this all the time with some added sea salt for flavor. You can also use it in dips or other recipes that call for cream cheese.