About 420 people were evacuated from the food factory after what is believed to be a pizza on a conveyor belt caught fire.
A spokesman for London Fire Brigade told FoodManufacture.co.uk: “It was not a massive incident and a sprinkler system in the building put the fire out.”
Firefighters inspected a pizza oven with a thermal imaging camera to check it was safe before leaving the factory.
A spokesman for the firm said: “Staff were evacuated safely and successfully, in line with procedure and the brigade were called as a precautionary measure.
“The factory was back to full operation within a couple of hours and the fire caused no substantial damage.”