If you happen to have the same fridge as me, there are two screws put into the door surface right between the upper freezer and lower fridge. I believe they are so you can swap the direction the fridge opens from side to side. They are mounted just right to add a small flat panel with some cutouts to the side that allow you to insert a rope, with a knot on the end, to "lock" the fridge from inquisitive toddlers.
In the photos, you can see some scrap material used as a rope however I later picked up some ~3mm paracord and found this would work well too (and it looks a lot better too although once you start safety proofing for kids, looks are pretty low down on the list after a year or two).
(and yes, I see a bit of cleaning on the fridge door is needed!)