Frozen food sealing. When vacuum sealing food to put in the freezer, it’s important to pre-freeze some items such as fruits, vegetables and meatballs on a cookie sheet. Foods that contain liquid should be placed in plastic containers before freezing. This will then allow the user to pop the food out and vacuum seal it in its frozen state. If a food is known to freeze well, double any amount of that item and immediately vacuum seal the extra. Always remember to use the bags specific to the vacuum sealer machine being used. Most of the bags can be cleaned and reused except those used to store raw meats.