Norcold Double Door Fridge - Model 1210

In the past week every time we open the doors of the fridge we get a peculiar odour. It sort of smells like warm plastic or maybe rubber. Can't really peg down the smell, but it is strong and clings to the outside of every bottle and can. We've removed everything from the fridge and wiped every item plus the interior of the fridge. No joy. The smell inside of the fridge seems to be strongest in the left bottom. There is no smell outside of the fridge either inside of the trailer or outside of it.
Anyone ever had a similar problem?