how do you remove food stains?

Cold water first, always. Hot water cooks protein stains like egg, dairy and gravy into the fabric. Rinse from the back so you push it out rather than through. After that it depends on the stain - greasy ones get washing up liquid worked in, tomato, curry and wine want a stain remover or an oxygen bleach soak. Check it's gone before drying, the dryer is what makes it permanent.