## Pulled Deli Ham From the Fridge and Noticed a Rainbow-Like Shine on the Slices. Is That Normal?
You’re halfway to making a sandwich when you notice something unexpected. The deli ham you just pulled from the fridge has a strange, shimmering sheen. When you tilt the slice under the light, flashes of pink, green, and blue ripple across the surface—almost like an oil slick or a rainbow.
The short answer is yes—**in most cases, a rainbow-like shine on deli ham is completely normal**. It’s a well-documented phenomenon tied to how light interacts with the structure of meat, not a sign of contamination or rot.
Still, food safety matters. Let’s walk through why this happens, what it means, and when you *should* be concerned.
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## The Science Behind the Rainbow Shine
That colorful shimmer has a name: **iridescence**.
Iridescence occurs when light reflects and diffracts across tightly packed surfaces, breaking white light into visible colors. You’ve seen it before on soap bubbles, peacock feathers, CDs, and oil on water.
Deli meat—especially ham—is a surprisingly good candidate for this effect.
### Why Ham Is Prone to Iridescence
* Sliced very thin
* Cut across the grain
* Kept moist
* Viewed under bright or direct light
…they can reflect light in a way that produces a rainbow-like sheen.
This is **purely a visual effect**. No chemical reaction. No bacterial activity. Just light behaving strangely on a microscopic surface.
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## Does This Mean the Ham Is Spoiled?
This is the most important question—and the answer is reassuring.
**Iridescence alone does not indicate spoilage.**
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