How do food industries find the calories of food?

Question

I'm doing a science fair on experiementing to find the calories in food. I was wondering, how do the food industries come up with the given calories to put up on the labels? all search engines give me is how many calories food contains and how to burn them......... :((
thanks

Answer 1

They have an instrument called a bomb calorimeter. It is an enclosed tank that can hold the food and has instrumentation to tell temperature. After they put the food portion in there they ignite it (with an electrical spark or equivalent). Then they watch how much the temperature rises. That rise is due to the energy given up as the food in there burns, which is the caloric energy of that food.

Sometimes instead of a real test they just use a reference that tells how many calories are in each ingredient and they compute how much total calories result from the known weights of each ingredient. That is obviously cheaper and faster.

Answer 2

You literally need to burn a food item to come up with how much calories it is. A calorie is a unit of energy. Here is a definition and below is a website that explains very well what a calorie actually is (means).

"What is a calorie?
(Lansing State Journal, May 8, 1996)

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This question brings up the topic of how scientists measure energy. Energy can take many forms. One form energy can take is heat.

The calorie is a unit used to measure heat. It is defined as the amount of heat needed to raise the temperature of 1 gram of water by 1 degree Celsius. If you want to raise the temperature of 10 grams of water by degree Celsius, it would need 10 calories of energy; to raise the temperature of 10 grams of water by 10 degrees Celsius, would likewise cost you 100 calories.

The calorie is often associated with food and dieting. Dietitians have measured the amount of energy that foods contain. If the body performs work (converting some of the stored potential energy into kinetic energy) and uses more energy than it consumes as food, the body will deplete its store of energy. Because a lot of the body’s stored energy is in the form of fat cells, a lifestyle that consumes more energy than it takes in can reduce the amount of fat in one’s body."

Answer 3

Calories are a measure of heat. The base unit, one calorie, is the amount of heat needed to raise the temperature of one gram of liquid water by 1° Celsius. Food calories, in particular, are the potential energy (heat) that food generates when eaten. A food calorie is defined differently from the standard calorie used in chemistry and physics. One food calorie is the amount of heat needed to raise the temperature of one kilogram (or 1 liter or 2.2 pounds) of liquid water by 1° Celsius. Therefore, a food calorie is 1,000 times as great as a standard calorie.

Answer 4

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