A method and apparatus for temporarily refrigerating perishable items contained in a refrigerated truck or trailer whose refrigeration unit is not functioning properly or at all. The apparatus comprises a portable, auxiliary refrigeration unit adapted to be transported to the refrigerated truck or trailer and includes a sealing element configured and adapted for placement in or adjacent a door opening of the refrigerated truck or trailer to provide at least a partial seal thereat. A chilled air duct is provided for delivering chilled air through/across the sealing element to the perishable items inside the refrigerated truck or trailer and the portable, auxiliary refrigeration unit is operable to deliver chilled air through the chilled air duct and into the interior of the refrigerated truck or trailer.