The primary sugar in milk and dairy products is
a. lactose
b. fructose
c. sucrose
d. maltose

The primary sugar in milk and dairy products is Lactose. Lactose (C12H22O11) is a disaccharide sugar from the reaction of galactose and glucose. Milk contains around 2% to 8% lactose by weight.

Lactose has many applications in the food industry. One of the most important is the addition of lactose in infant formula milk. This is needed to simulate the composition of human milk.