Vacuum / Aerobic + High Oxygen Packaging & Meat Quality - Detrimental Effects

Detrimental Effects of Aerobic & High Oxygen Packaging on Meat Quality: 2x Higher Lipid & Cholesterol Oxidation, Less Tender, More Drip Loss, Less Juicy... but More Convenient! - SuppVersity: Nutrition and Exercise Science for Everyone

Good to now it's protected! Right?

If you ever bought a product like that you will have realized that you can easily store it for the whole 7day+ period in you fridge and - as long as the airtight plastic container is not broken - it will look and smell almost as it did on day one, when you rip the container open and take a closer look, whether the meat you are about to prepare is still good to eat; Looking good!

What you cannot see though, is that the "protective atmosphere" protects, may have protected the looks of the meat, but not its nutritional quality. 

I mean think about it: What happens when you put metal into a wet high oxygen environment? Right! It starts to oxidize. Now guess what has happened to your appetizing piece of chicken, beef, pork or lamb while it was (highly conveniently, obviously) waiting for you in your fridge. Right it began to rust.

Figure 1: Content of cholesterol oxidation products (COPs) in non-irradiated raw chicken/turkey leg and raw beef with packaging, and storage time; data expressed relative to baseline (Nam. 2001)
As the data in figure 1 goes to show aerobic packaging (this is not yet a high oxygen environment) accelerates the rate of lipid and protein oxidation, so that the content of potentially hazardous cholesterol oxidation products (COPs) in your turkey legs, raw beef on day 7 is anywhere between 20-100% higher than on day one.
"Although the packaging conditions of meat during storage were critical for the oxidation of cholesterol in raw meat, irradiation synergistically increased it." (Nam. 2001)
And as Nam et al. point out this effect is even more pronounced if the meat has been irridated before packaging. The vacuum packaging, most producers and vendors are reluctant to use, because the meat does not look anywhere as fresh as the one that's packaged with highly oxygenated air (in fact it's the oxidized oxyhaemoglobin MbO2 that's responsible for the rosy color, cf. Rennere. 1999), on the other hand, "was enough to protect cholesterol and fatty acids from oxidation regardless of irradiation dose." (Nam. 2001)

Red deception in the "fresh" food corner

Figure 2: T-bar levels (a marker of lipid oxidation) in air, high oxygen and vacuum packaged pork during refrigeration for 0-20 days (Cayuela. 2004)
Now, with normal air, the nice red color will at some time give way to a brownish one, with extra high oxygen air that's used in high oxygen packaging, it will prevail, but at the same time,
"[t]he use of modified atmospheres with a high oxygen concentration (70%) act[s] as a pro-oxidation factor both for fatty acids and for cholesterol (an increase of 86.4% on the initial COPS content)." (Cayuela. 2004)
And that's a plus of almost 90% on top of what you would see with "regular" air packaging, as it was used in the Nam study.

Ah, and did I mention that this "meat" will also be less tender, less juicy and will have a 4-6x higher drip loss than "regular" packaged meat, when it's stored at 4°C for several days (Lund. 2004).