How do food producers measure the exact amount of carbs, proteins, vitamins etc. in a piece of food?

Question

How do food producers measure the exact amount of carbs, proteins, vitamins etc. in a piece of food?

In: Biology

Answer 1

Carbs is done by burning said fuel to heat a certain amount of water. There is a chemistry equation that takes change in temperature divided by amount of water plus some other Hocus Pocus to derive cal content of said item that was burnt.