A large fire tore through Greerton Produce in the early hours of yesterday morning, causing a "substantial amount of damage" to the local business.
Fire investigator Bill Rackham said the fire started near electrical equipment, possibly because of an electrical malfunction.
Mr Rackham said the area where the fire started was "totally destroyed".
Polystyrene in the chiller of the building added to the fire and caused damage to the roof, making the building unstable, Mr Rackham said.
The fire was not being treated as suspicious. The cause would be confirmed after working with forensic examiners.