Bright red piece in/on stool. neither toilet water nor paper was red. what are the chances this could be blood? could it possibly be "skin" from food?

Needs evaluation pls: Blood in stool is a warning sign. Brisk bleeding warrants emergency care. Causes of bleeding may be predictable (e.g rectal trauma), but evaluation is always appropriate. A rule of thumb (but not absolute): black stool means bleeding comes from upper GI tract; grape jelly stool from small bowel; silver stool from biliary tree; burgundy stool from right colon; red blood from left colon to anus.

. Hard to say: Unless you are having any other symptoms would be unusual to be anything serious. If you develop more issues should save the material and see your doctor.