Should a fly be dipped if it falls into a baby's milk and is drunk, or should food be thrown away if a mouse falls into it?

If a fly falls into a vessel, it is not obligatory to immerse it in it, for the command in "let him dip it" is not a command of obligation but rather a guidance. It is not obligatory to drink this milk or give it to a child, so whoever dislikes it is not at fault. The ruling on a mouse or its carcass falling into food differs depending on the type of food (solid or liquid).