Why Does Meat Sometimes Look Rainbow-Colored?

You open the fridge, reach for a slice of roast beef—and freeze. Gleaming across its surface: a shimmering arc of emerald, gold, and violet, like oil on water or a hummingbird’s throat in sunlight. Your mind races: Is this safe? Did it go bad? Did someone… dye it?

Relax. That iridescence isn’t spoilage. It’s not magic. It’s science—a quiet, dazzling dance of light and structure happening on your deli meat, and it’s completely harmless.

 The Why: When Meat Becomes a Prism

Meat isn’t a uniform slab—it’s a tightly woven tapestry of muscle fibers, aligned like piano strings. When deli meats (especially whole-muscle cuts like roast beef, corned beef, or turkey breast) are sliced across the grain, those fibers are cleanly severed, creating microscopic ridges on the surface—think of them as nature’s diffraction grating.

Now, enter light:
→ White light (from your kitchen bulb or the sun) hits these ridges.
→ The grooves split the light into its component wavelengths—just like a prism.
→ Different wavelengths (colors) reflect at slightly different angles.
→ Your eyes perceive this as shifting iridescence: rainbow meat.

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