Meunerie Côté-Paquette incurred an estimated $20 million in damage when it caught fire on Feb. 23.
A suspect was arrested following that incident and remains in custody.
Tuesday morning's fire started in a warehouse that wasn't damaged in last week's fire.
Highway 235 was closed in both directions in the area.
A Quebec provincial police spokesperson said the suspect in the first fire will be detained until March 11, when he is scheduled to appear for a bail hearing.
Meunerie Côté-Paquette produces feed for animals.