So you are standing in front of the meat case wanting to purchase a package of ground beef. You definitely want the freshest product available and we all know that when buying meat, especially ground beef the color red means it is the freshest. Or does it.
Looking at the picture below, which package would you say was the freshest?
Both packages were purchased on a Monday at the same time. The package on the right had a sell by date of Wednesday of that week. The package on the left had a sell by of the following Wednesday. Yes, one week later than the package on the right.
How is this possible? The package on the left is vacuum packaged while the one on the right is placed in a styrofoam tray and wrapped in a plastic film. Both are placed on the grocers meat shelf for us to purchase.
Vacuumed packaging is the removal of air from the package and without air, especially oxygen, bacteria growth is slowed tremendously. But, because of the lack of oxygen the meat does not "bloom".
Now we are not going to get into all of the chemistry of what actually happens to meat as it blooms but let's take a few minutes to briefly explain it. And for this discussion we will be talking about beef, however the same principle will hold true for other species such as pork, lamb, and veal.
When one first cuts a piece of beef the newly exposed muscle will be a very dark purple. In fact, sometimes, it may even appear almost black. However after 15 - 30 minutes this dark piece of freshly cut beef will "bloom" into a nice bright red cut. What causes this? The answer is oxygen. By exposing this cut to air, the oxygen combines with the protein molecules (specifically iron atom) and when this happens, the beef turns bright red.
So why doesn't the beef cut or grind stay bright red? Well, guess what the answer is? Yes, the same oxygen is a contributing factor. Because when you first cut or grind that beef you are exposing it to not only the air, but also to bacteria. The meat provides food and moisture for this bacteria and the package on the right allows the meat to be exposed to the oxygen that the bacteria needs to grow and multiply. And, again, let's avoid a lot of the chemistry, but suffice it to say that the increased bacteria will start to change the ground beef from that bright red to a brown color. The brown color that we associate with spoiled meat.
However, the package on the left is vacuum packaged. And remember what we just learned, that when beef is first cut or ground it might take up to 30 minutes to turn that bright red color we like. So by removing the air from this package, the ground beef will remain that dark color that you see in the package on the left.
By the way, both of these are natural ground beef with, besides packaging, the only difference is the vacuum package is 91% lean while the other is 92% lean. So for this discussion, both are considered equal.
The picture below is of the same two packages after 4 1/2 days in my refrigerator at home.
And you can see what the bacteria being exposed to oxygen did to that bright red package of ground beef that we saw at the top of this article. But remember, oxygen is what made the package red to begin with. This browning of the meat in the package on the right is because of bacteria and the meat is not good. It had a foul order to it.
Remember the original sell by dates on both of these packages. At this point the vacuum packaged product still has approximately 5 days left. And the tray wrapped product was already outdated.
And so now you wonder what the vacuum package of ground beef would look like if I open it up. So I waited one more day. And look at the difference one day makes. The bacteria are really multiplying on the tray wrapped ground beef. I opened up the vacuum packaged product. It had a fresh odor to it and look at the "bloom" it had after about 30 minutes .
But now that I have exposed it to oxygen and bacteria, it will look like the package on the right in a few days.
So in conclusion, the vacuum packaged beef gave me the flexibility of purchasing this package today and not be concerned about having to use it or freeze it in a few short days. The vacuum packaged product is not bacteria free but the lack of oxygen has really slowed the bacteria growth while in the tray wrapped package, the product is constantly exposed to oxygen that assists the bacteria to grow more rapidly.
The vacuum package also, if I needed to is a package that I could just place into the freezer and not have to repackage like the tray wrapped product would require.
A negative about the vacuum package is the cost is more for the manufacturer, so it will cost you more.
As you might be able to tell, I am fond of the vacuum package.
If both packages were ground and packaged the same day, knowing what you now know, which would you buy?