Q How can milk make so many different products?
— Ruby Taggart, Merrimac, Wis.
A Scott Rankin, professor and chairman of the food science department at the University of Wisconsin-Madison:
Milk can make many products because of its complex chemistry and history. Early humans used milk and had to experiment with various means to preserve it and its nutrition content over time, using things like salt and freezing.
Milk from mammals is the sole source of sustenance and growth nutrition-wise for infants. Milk is complex and the only food designed to really sustain life. You can drink only milk as a young infant and still grow.
When humans started to domesticate mammals, they began to realize that mammals made a lot more milk than what was needed for growing their offspring. They had surplus milk, and humans started to take different approaches to preserving it.
The main component of milk is lactose. If you let milk just sit, all that lactose will start to ferment, and acid will develop. This begins the path to yogurt or cheese. If you take yogurt and add a lot of salt to it, which is another means of preserving milk, it starts looking more like cheese, things like cheddar and mozzarella and Parmesan.
Freezing milk is another way to preserve it, and this preservation technique is likely the predecessor of ice cream.
Good-quality milk is very bland in flavor, so it has been a vehicle for delivering a lot of different flavors. Milk worked with a lot of those flavors and allowed for variation to the diet.
There are many animals from which humans harvest milk, and each produces milk with different characteristics and chemistry. Cow’s milk, goat’s milk, sheep’s milk, and horse’s milk, for example, all have unique characteristics that drive unique products.
When you think about mozzarella, pizza cheese and Caprese salad may come to mind. Mozzarella really came about because there’s a region in Italy that supported water buffalo. Cows could not thrive there, but water buffalo could. Humans took the milk, and eventually mozzarella was born.