I slow cooked a pork roast for 8 hours, but when I sliced it, I saw this weird shiny green and rainbow reflection on the meat fibers. It looks like gasoline on water. Did the meat go bad?

10. Tips to Reduce the Rainbow Effect
If you’d prefer to minimize the iridescent look:

Slice against the grain at a steeper angle.

Let the meat rest before slicing.

Use a sharp knife for cleaner cuts.

These adjustments can reduce visible light diffraction without affecting flavor.