In all games, the fridge will be in Darkness' Kitchen, but he will only be important in the Salad Liberation storyline.
In the Salad Liberation storyline, Carrot asks for Sam's help to get his fellow carrot allies out of Fridge in exchange for returning Sam his mask.
When Sam arrives to Fridge, he tricks the Fridge into thinking he has come to imprison Carrot into him. Fridge falls for this and opens his door in order to let Sam put Carrot into imprisonment. However once he does that, Sam and Carrot reveal to the other carrots that Sam and Carrot are allies and that the carrot allies are now finally free. The Salad Liberation Front then escape Fridge and Carrot returns Sam his mask before leaving to rejoin his fellow carrots.