"troubleinstore" wrote in message ...

Two possibles come to mind.

Check if there's a drain tray behind the fridge and freezer. They're
supposed to collect and evaporate condensate and are sited on the
black compressor can, usually at the bottom. They can collect milk,
orange juice etc., which ferments in the heat. I once rented a holiday
flat which had an apalling pong , due to this.

Also, any indoor soil & vent pipes, probably in ducts, or a defective
air admittance valve, usually in the loft? A cover may have been left
off. You can get the drains smoke tested to locate any leaks, but I'm
not familiar with the details.