- you should have received two door airing props (one each for the upper and lower doors) when you picked up your new trailer. Many people (sale staff included) don't know the purpose of these parts and they often get overlooked or discarded. There are prop variations (matched to different refrigerator models/vintages) but I chose this link as one that likely matches your new unit. Match the refrigerator model number to acquire the correct props.
De-ice and clean out your reefer after each trip; wipe down the interior with a dilute mixture of vinegar and water, place an open box of baking soda or a sock filled with ground coffee beans inside, and use the aforementioned airing props to close and latch doors which will then remain open a crack for ventilation.