Can I defrost and cook in the same bag?

A user asked us the following question:

If I want to use the sous-vide method on a product that I’ve already vacuum sealed and frozen, can I simply let it defrost and cook it in the same bag or do I need to use a new bag?

Here is our chef’s answer:

If the bag is still vacuum sealed and the structure is in good condition, you don’t need to change it. Nevertheless, you should consider if the bag you’d like to use for cooking can indeed be used for cooking. There are certain bags that are only for storage (up to -80ºC [-112ºF]) and only for cooking (over 80ºC [ 175ºF]).