Why Some Steak Stays Red Longer
Influence of Age at Harvest and Packaging Conditions on Color Stability of Bovine Psoas major Muscle
Not medical advice. For informational purposes only. Always consult a healthcare professional. Terms
Surprising Findings
CO-MAP eliminated age-related color differences entirely, despite older cows having 20% more myoglobin.
Previous studies claimed older beef always discolors faster—this shows packaging can override biology, which contradicts decades of meat science assumptions.
Practical Takeaways
If you’re a retailer: Use CO-MAP to reduce returns from discolored beef. If you’re a consumer: Check expiration dates and smell meat—even if it’s bright red.
Not medical advice. For informational purposes only. Always consult a healthcare professional. Terms
Surprising Findings
CO-MAP eliminated age-related color differences entirely, despite older cows having 20% more myoglobin.
Previous studies claimed older beef always discolors faster—this shows packaging can override biology, which contradicts decades of meat science assumptions.
Practical Takeaways
If you’re a retailer: Use CO-MAP to reduce returns from discolored beef. If you’re a consumer: Check expiration dates and smell meat—even if it’s bright red.
Publication
Journal
Foods
Year
2025
Authors
Xiao Lu, Xin Luo, S. K. Matarneh
Related Content
Claims (6)
When meat is exposed to carbon monoxide, it turns and stays red—even if it's going bad—so it looks fresh longer, even though bacteria might already be growing inside.
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.
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.
Meat from older cows looks darker than meat from younger cows because it has more of a red pigment called myoglobin—but if you wrap it in special gas packaging with carbon monoxide, both types of meat end up looking the same bright red.
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.