we have 4 dogs. Their food is stored and prepared in a small treyf kitchen built onto the back of our garage. The refrigerator/freezer, stove and keilim are not used for humans. The door is kept locked and only Mrs. CTLAWYER and I have the keys. Our children were never allowed to prepare or serve the dogs’ food.
As to bleach, we often use it in the sink and it may get on keilim, so a hechscher is nice even if not required. Laundry detergent or floor cleaner with a hechscher is just a way for the kashrus organization to raise money.