[Arran]

 Unless it's a very old fridge, like one from the 1950s, with a mechanical latch, I would not even entertain trying it.  By the time you construct this thing, you could have dunked the entire cabinet in kerosene, pesticide, or baked it in the oven several times to kill the bugs, maybe the antique restorers have such a device but I can guarantee that they didn't simply throw it together in an afternoon.
Regards
Arran