The lower compartment of your RV refrigerator should be a minimum temperature of between 34 degrees F to 43 degree F.
If your RV refrigerator is any warmer than 34 degrees F then your food could become spoiled and it would be unsafe to have your RV refrigerator any warmer than 34 F.
Always make sure your RV refrigerator stays cool enough and it's best to have a refrigerator thermometer so that you can easily check the temperature inside the RV refrigerator.
It can take around 10 to 24 hours to fully cool down an RV refrigerator so it's best to plug the RV into the power at least 24 hours before leaving out to allow your RV refrigerator enough time to cool down to safe temperatures.
Then you can use the propane to keep the RV refrigerator cooling down the food.