A method for improving the palatability of a livestock feed or companion animal food product comprising a basal composition containing unsaturated fatty acids that oxidize to form aldehydes or ketones by contacting the basal composition with a source of bisulfite anions so that any aldehydes or ketones present form organosulfite salts. Bisulfite-treated livestock feed and companion animal food products, and palatability enhancing composition containing a source of bisulfite anions are also disclosed.
