Being unsure whether food spoilage has occurred or not. Does not have to be a milk product, but milk is so vulnerable that everything (including life!) starts from there, including expressions. Plus, its always hardest to tell whether milk products are actually bad.
I was looking at that feta, and I had some real milk doubt about it.
This pizza smells funky, so I'm feelin' some milk doubt.
I don't know, this salad dressing looks rancid, I am experiencing major milk doubt. What do you think?