Will Carbon Monoxide Cause You to Buy Spoiled Meat?

Have you ever wondered why some meat starts looking brown after a few days in the meat case at the grocery store, while other meat stays fresh-looking longer? Some meat is packaged in an atmosphere high in carbon monoxide, as opposed to normal air. The carbon monoxide binds to the myoglobin (a protein) in the meat to cause it to look the pink color most of us associate with fresh meat. The chemical reaction that causes the color fixation doesn't present a health hazard, but there are concerns about consumer safety because people buy meat according to how it looks. Meat that has been packaged in a carbon monoxide-rich atmosphere will continue to look pink past the point when it should be sold. Untreated meat gets darker in color as it stays on the shelf. Of course, there are other indicators of freshness. A slimy appearance is a giveaway of decay, as is bulging packaging from the gases produced by bacteria. If you could smell the meat, you'd know whether or not it's good, too.

Anyway, it's an interesting application of chemistry in our day-to-day lives. There's no labeling on meat to let you know whether or not carbon monoxide packaging has been used, but you can still figure it out. The next time you're grocery shopping, take a look at the meat that has been marked down because it's close to its sales date. Has the meat started to deepen in color and become more brownish? Is it a vibrant pink? If it never changes color, you can be sure the color was fixed.
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