"צביעה באוכלים" (coloring in foods) - the stringent view of some poskim
Is There a Problem with Spreading Foods (e.g., Peanut Butter, Cheese, Hummus, etc.) onto Challah, Matzah, etc. on Shabbos?;
Does This Melacha Apply to Other Materials Besides Leather?;
מחמת חסרון כיס Machmas Chesron Kis: Raw Meat;