The Benefits of Vacuum sealing
“Cryovac” is food-industry shorthand for “vacuum-pack”—meaning to wrap foods in impermeable plastic, then remove most of the air inside the package to prevent oxidation (causing rancidity or darkening in colour) and inhibit the growth of most pathogens—both important factors in a food’s decay, or spoilage.
We're now vacuum sealing most items for online orders. This removes all the oxygen from contact with the meat and effectively puts the meat in an environment that doesn't break down. Vacuum sealing vastly improves the shelf-life of the meat. For example, beef mince will normally last 2-3 days in a cold fridge but when prepared like this it should last easily a week (depending on how long it was exposed to air first).
When we vac-pack steaks joints and prime cuts we're actually wet-aging the meat. This means the meat is undergoing a controlled slow break down process that intensifies the flavour. A vacuum sealed prime steak or joint will last 2 weeks in the fridge.
One tip is to open it up and let it breathe for an hour or so before cooking. Don't be put off by a smell that often comes when the bag is first opened. This is caused by the meat sweating in the vacuum environment and is totally normal and quickly disappears when exposed again to oxygen. Also most discolouration will quickly come back to normal with red meats after some time in normal oxygen rich air.
Other benefits include that vacuum sealed food will freeze better. As its impossible to develop freezer burn, and what's more that when it comes time to defrost the impermeable layer is very handy when submerging the item in water (always the best method!).