For many meat eaters the proof is in the pink. They use the meat's color as a guideline to determine the food's freshness. But, many meat manufacturers actually inject the food with carbon monoxide to give it that fresh, reddish-pink look.
Japan and Canada along with many other countries in Europe, have banned the use of carbon monoxide in meat. Lawmakers in congressional hearings this week are debating whether the producers should be allowed to continue the process in the United States.
While the Food and Drug Administration has said the practice isn't dangerous, some consumers disagree.
"At worst, it's dangerous. At best, it's a consumer rip-off," said Wenonah Hauter, of Food and Water Watch.
But, industry manufacturers have defended their use of carbon monoxide-treated meat. The problem arises because even perfectly good meat begins turning brown when it's exposed to oxygen. So, many meat manufacturers treat beef and pork with carbon monoxide.
The carbon monoxide binds with a pigment in the meat and keeps the colors vibrant and red.
"What this packaging technology allows us to do is to maintain the red color consumers are used to purchasing," said Randy Huffman, of the American Meat Institute.
Yet, during the hearings some Congress members couldn't be swayed and grilled the companies about the practice. They called the practice unsafe and misleading, and to make their point, they displayed a 2-year-old package of meat that still looked pink and fresh, thanks to carbon monoxide injection.
"One of the packages in front of you is 2 years old. Is that not a problem?" asked Rep. Jan Schakowsky, D-Ill.
"It is critical that the use-by date be adhered to," Daniel Engeljohn, of the USDA food safety and inspection service responded.
Rep. Bart Stupak, D-Mich., and chairman of a House Energy and Commerce subcommittee, reportedly called the practice deceptive and "a potential health threat," and accused U.S. regulators of "turning a blind eye" toward health dangers.
Earlier this year, Stupak launched a probe into the practice and has proposed the use of a safety notice on meat and fish products treated with carbon monoxide.
In response to consumer concern, some grocery chains like Harris Teeter, which has locations in five Southeastern states, have voluntarily stopped treating meat with carbon monoxide.
Over the last month, Safeway, Giant, Stop & Shop and Tyson Foods have all announced they will stop using carbon monoxide.
Retail giant Target took a different approach and asked the FDA for permission to put carbon monoxide labels on its meats.
Congress seemed unlikely to outlaw the practice and probably will settle for some sort of labeling instead.
Consumers who are unsure whether their grocery store allows carbon monoxide-treated meat and no longer want to use color as a freshness indicator do have other, safer options.
They should look for the freshness date. Because stores don't want to sell their customers bad meat, the dates should be accurate.
The meat also should feel springy to the touch and the fat should be white, not yellow in color.
The way the meat is packaged also can say a lot about its freshness. If the plastic packaging is about to burst, it could be a sign of gases, which have built up from spoilage.
Finally, the best sign of spoiled meat happens once the package is opened. Spoiled meat smells bad and has a slimy texture.