Rainbow Shimmer on Deli Ham! How to Tell If Its Safe or Spoiled

It’s a familiar moment of hesitation at the deli counter: you peel back the plastic on a fresh pack of ham, only to be greeted by a shimmering rainbow across the slices. Bands of oil-slick green, iridescent purple, and neon blue ripple over the pink surface, looking more like a chemical spill than lunch. For many, this dazzling display is enough to send the cold cuts straight to the trash. Yet the science behind this phenomenon—known as iridescence—is far less sinister than it appears, provided you can tell the difference between harmless optics and genuine spoilage. Why Ham Glows The rainbow…