Vacuum-sealed packaging can press muscle fibers tightly together, enhancing light diffraction and making iridescence more noticeable.
Brining may also align and swell muscle fibers, increasing the visual effect. While these factors can intensify the sheen, they do not indicate spoilage.
9. Simple Kitchen Tests to Tell Optical Illusion from Spoilage
To distinguish harmless iridescence from spoilage:
Inspect visually for mold or abnormal discoloration.
Smell the meat for sour or off odors.
Check texture for sliminess.
If the pork passes these checks, the rainbow sheen is almost certainly an optical effect.
