I don't know the history of this now-closed plant but the sign and the cinder block mural that borders the property are worth the trip to see.
... "Mentioned in the book 'Twentieth Century Folk Art Of The Americas', Australian-born artist Leslie Grimes arrived in California in 1928, where he worked as a scenery painter at the Fox and Charlie Chaplin studios. The former wrestler painted under contract from the Clougherty Meat Packing Company in the 1960s, on their plants in L.A., Fresno, Phoenix and Tucson, thus explaining the wall of Farmer John's Meats.... Most of the paint was laid on with rollers and huge brushes...." Excerpt from a 1990's TUCSON WEEKLY article