The bakery company will hold off on opening until mid-February, when it will close its plant in Wilson, according to the Morning Call.
The $75 million facility is on 30 acres that it has purchased at 105 Boulder Drive. The site is across from Ocean Spray's new plant.
Bimbo announced last year it was closing its Wilson plant, and urged workers there to apply for jobs at the new Upper Macungie operation.
Bimbo Bakeries, based in Horsham, became with largest baker in the country in 2002 and 2009 with the acquisition of the George Weston companies, which include brands such as Entenmann's, Thomas English Muffins and bagels, and Boboli pizza crusts.
Bimbo Bakeries is itself part of a larger company, the Mexico-based Groupo Bimbo, which began American operations in 1994.