I Took Deli Ham Out of the Fridge and Noticed an Iridescent, Rainbow-Like Sheen on the Slices

If you’ve ever pulled a package of deli ham out of the fridge and noticed a shiny, rainbow-like sheen on the slices, you might have wondered: Is this normal—or should I throw it away?

What Causes That Rainbow Shine?

The iridescent, rainbow-like appearance you’re seeing is often due to light reflecting off the meat’s surface, a phenomenon called structural coloration. In deli meats, the thin slices and smooth, moist surface can bend light in a way that produces a rainbow effect.

It’s not harmful in itself. In fact, it’s somewhat common in packaged, processed meats like ham, turkey, or roast beef. The effect is purely visual and doesn’t indicate spoilage.