Sam is making a smiley face with her slime, not eating it. Slime isn't exactly toxic, but it isn't food.
Anne Helmenstine
Store your slime in a sealed ziplock bag, preferably in the refrigerator. Insect pests will leave slime alone because borax is a natural pesticide, but you'll want to chill the slime to prevent mold growth if you live in an area with high mold count. The main danger to your slime is evaporation, so keep it sealed when you're not using it.