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Carbon Monoxide in Meat

Consumers expect red meat to be red — not some unappetizing brown color. Problem is, even when refrigerated, meat starts to turn brown the minute it comes into contact with oxygen in a chemical reaction called oxidation. The meat industry's solution: Inject a mix of gases containing nitrogen, carbon dioxide, and carbon monoxide into tightly sealed packages of beef, lamb, and pork. This "modified atmosphere" doesn't include "free" oxygen, so it won't trigger oxidation and keeps meat red and freshlooking until the package is opened.

The Potential Danger
"Consumers use color as a cue to freshness, and this process takes that information away from us," says Barbara Kowalcyk, director of food safety at the Center for Foodborne Illness Research and Prevention. "Such treated meat could be left out in the sun on some loading dock during shipping, and nothing about its appearance would tell consumers it wasn't as fresh as it should be."

But in fact, modified atmosphere actually preserves freshness, counters Huffman. When oxygen is removed, the product lasts longer, because oxidation is what causes meat to become rancid. A far better guide to freshness is the sellby or useby date found on packages, says Huffman.

Should You Worry?
Wrapping meat with gases offers at least one safety advantage: Packaging is done at one centralized location instead of in your grocer's backroom butcher shop, so meat is handled less, reducing potential exposure to harmful bacteria. What's more, there's nothing inherently unsafe about the gas itself. The problem is that consumers can't tell for sure when the mix has been used because that information isn't on the label. (One clue: Treated packages typically use deep trays with space between the meat and the plastic film, which is stretched drumtight.)

But Kowalcyk insists it's still a righttoknow issue: "At the very least, labeling should indicate which meats have been treated." In a 2004 review, the Department of Agriculture's Food Safety and Inspection Service agreed that if meat goes bad, carbon monoxide could mask spoilage. Yet the FDA, which has the last word, continues to give the process its blessing.

The bottom line? While there's a theoretical risk, and product labeling would be a good idea, in practice it's unlikely that meat in modified atmosphere is unsafe. "Packaged meat is one of the most important items in the grocery store, and retailers are very attuned to quality," says Huffman. "More than 200 million of these packages have been sold with virtually no problems."

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