When you wrap beef from older cows in regular plastic or air-filled packaging, it turns brown and goes rancid faster than if you use carbon monoxide packaging — and the older the cow, the worse it gets.

Using carbon monoxide in meat packaging helps keep beef looking red and fresh for two weeks by preserving its natural ability to hold oxygen and stay colorful—unlike regular plastic wrap or high-oxygen packaging, which make the meat turn brown faster, especially if the cow was older.

When you wrap beef in a special gas-filled plastic that includes carbon monoxide, it stays bright red longer and doesn't spoil as fast as when wrapped in regular plastic or air-filled packaging—even if the cow was young or old.