How do canned soup companies keep their noodles from absorbing all the liquid in the can?

I like to make noodle soups. Chicken noodle, pho, k'tieu, soba, and so on; there are many different types of noodle involved. In every case, if the soup goes into the fridge, the noodles absorb all the broth fairly quickly. Typical fixes for this include:

• cook the noodles separately and add to the soup when serving;


• freeze the leftovers;


• eat all the soup right away!

But when I buy canned soup from the grocery store, the noodles are never blown up and they don't seem to blow up even after opening the can and leaving summer in the fridge.

What is the secret? Is it a special kind of noodle, something about the broth or a heavy duty industrial preservative at work?