Which would translate to rancidity of the fat component. that's no good. not only does that make for an awful flavor, but most arterial damage comes from eating oxidized fats.
https://photos.app.goo.gl/WxmwkhhNV2r7NMtt9
I buy this high quality, flavorful parmigiano reggiano in medium size wedges they sell at this posh local grocery chain. If what's left here is still good, I have enough to make pesto. The internets vary widely on how long this stuff lasts, some...