The fire at the plant, located on the outskirts of the city, was triggered by a short circuit last night in the unit's packaging department, police said.
Within a short time, flames had engulfed major portions of the plant including its freezer and processing departments.
Aligarh division DIG Prakash D told reporters that over 100 fire tenders from at least five surrounding districts had been deployed to tackle the blaze.
The DIG said that an even bigger disaster was averted as fire-fighters doused the flames before it could spread to the plant's chemical store where a large quantity of chemicals, including fuels, were stored.
Although there was no official estimate regarding the losses in the accident, preliminary calculations suggest that the total damage is likely to exceed Rs 100 crore.