Should We Fear Our Food?
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
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."
It sounds like something out of Star Trek : Make food safe by
killing germs with an invisible ray. But there's nothing fictional behind the
science of irradiation, a technology in which prepackaged food is exposed to
gamma rays from radioactive substances, shot with electrons from an electron
gun, or zapped with Xrays. The highenergy beams or rays kill most, if not all,
dangerous microorganisms such as E. coli by breaking apart molecular
bonds in their DNA.