How does replacing the air around stored food with nitrogen gas keep it from spoiling?

Question

How does replacing the air around stored food with nitrogen gas keep it from spoiling?

Answer 1

Some foods, such as coffee, react with the oxygen in air and develop a bad taste. Coffee bags sometimes contain a one-way valve, allowing you to squeeze out the air. If you'd like a simple experiment to show how air changes food, cut an apple in half, and protect one half from the air (you might coat it with oil). The exposed half changes color in a few minutes. BTW, when baking, lemon juice, or orange juice is used to keep apples looking fresh. The citrus fruits have vitamin C, AKA ascorbic acid, which reacts with oxygen before it get to the fruit. Hmm... a better experiment: bake and eat an apple pie. :-)

Answer 2

It does not entirely stop spoiling but it will slow it down by killing organisms that need oxygen to live. The nitrogen displaces the air thereby removing the oxygen in the air from contact with the food. There are decay organisms that do not need oxygen to live so this technique will not completely protect food from spoilage.