Family member sharing utensils/drinks with toddler

Hey ladies! We have asked our family to please not share utensils/straws with our toddler because it transfers germs/mouth diseases to them and everyone BUT my sister has willingly obliged. My sister is a heavy smoker so we especially do not want her sharing. She agreed but continuously does it behind my back then apologizes when I confront her. What can I do with this situation? She obviously doesn't respect my wishes