Is Darkening on Rested Red Meat a Sign of Spoilage?

The dark red-brown color that develops on the surface of butcher-bought or home-rested red meat usually isn't spoilage; meat naturally darkens through oxidation once it's exposed to air, and that change alone isn't a warning sign. How do you tell natural darkening from spoilage?With natural darkening, the meat's interior still looks bright red when cut, and the color change is limited to the surface that's been exposed to air. With spoilage, the color shifts to a gray-greenish tone, spreads throughout the meat rather than staying on the surface, and is usually accompanied by an off smell. In dry-aged meat, a dark, or even hardened, crust on the surface is expected and normal; that crust is trimmed off before cooking, and the meat underneath is eaten for its concentrated flavor from aging. The real thing to check in this kind of meat is whether there's a sharp, ammonia-like smell underneath the crust — if there is, the aging has gone too far and the meat has spoiled. What do touch and smell reveal?Fresh or properly aged red meat feels springy to the touch; press it and the surface bounces back quickly. Spoiled meat loses that springiness, feeling soft, loose and tacky instead. A shiny, slimy film on the surface is also a typical sign of spoilage. Fresh meat is nearly odorless or has a faint bloody smell; spoiled meat develops a sharp, sour or ammonia-like odor that doesn't cook away. If you notice that smell, don't eat the meat even if the color still looks normal. A brief, mildly sour smell right when you open vacuum-sealed red meat is normal and usually fades within a few minutes of air exposure. If that smell lingers and keeps getting stronger, the meat really has spoiled. What do lighting and packaging color change?Lighting affects how meat looks in a butcher's display case too; red-tinted display lights can make meat look more vivid than it really is, so judging its true color is more reliable under natural light when possible. The dark, almost purplish color vacuum-packed meat develops while sitting in the fridge is also natural; once the pack is opened and the meat meets air, it turns bright red again within a few minutes — that shift is oxidation, not spoilage. Ground red meat spoils far faster than a whole cut; passing through the grinder dramatically increases the surface area exposed to bacteria, so darkening in ground meat shouldn't be treated as harmless the way it is in a whole cut — ground meat should be cooked or frozen the same day it's bought. Seasoning or marinade on the surface of meat can sometimes be mistaken for darkening; with marinated meat, gently wipe away a bit of the marinade and check the color and smell of the meat underneath, and discard it if the color is off or the smell is bad. Normal color and smell alone do not prove the meat is safe; cook it only if it has been kept in the refrigerator and is within its storage time.