It is important to note that not all plastic bags are suitable for sous vide cooking and so it is essential users cook with food safe resealable bags or vacuum pouches. These are traditionally made from Polyethylene, but you should always check the bags / vacuum pouches you intend to cook with are food safe before using them.
Another important consideration is correct serving and storage of sous vide food. If serving immediately, simply remove the ingredients from the bag once cooked, sear if desired and serve.
If serving later, place the bags into an ice bath to cool before refrigerating. The quick chill method ensures food remains safe for eating later. To reheat - simply place the food back into the sous vide water bath, once the food has reached its original cooking temperature, it is ready to serve.
A third consideration is to ensure bags are fully submerged in the water so that ingredients are cooked thoroughly.