Suffolk Fire and Rescue Service was alerted to the leak at 4am, after an alarm in a non-production building at the factory was activated.
Fire fighters used four breathing apparatus and one hose reel jet to isolate the leak, with the situation under control by 5:07am.
Birds Eye said the incident was dealt with by its on site technical team, who followed established emergency procedures.
‘The safe management of this incident’
Lowestoft supply chain director Craig Hamilton said: “We’d like to thank our colleagues and the emergency services for their quick actions this morning, which led to the safe management of this incident.
“The safety of our people is our highest priority and we will be conducting a thorough investigation to avoid this happening again.”
The factory was not evacuated and no one was injured as a result of the incident. It remained fully operational and production was not affected in any way.
Birds Eye said the safety of its employees was its highest priority and it would be conducting a thorough investigation to understand how the leak happened. It would take necessary measures to avoid another incident happening.
The incident at Birds Eye Lowestoft is the second ammonia gas leak to occur at a food business this week.
‘Controlled ammonia leak’
Staff at part of Addo Food Group’s Poole factory were evacuated last week, after what the firm described as “a controlled ammonia leak” at the site.
A spokesman told FoodManufacture.co.uk that the emergency services were not called and no one was injured.
“Our Poole Bakery site was carrying out planned maintenance on an isolated section of its ammonia refrigeration plant which resulted in a small, controlled leak,” said the spokesman.
“As a precaution, part of the site was temporarily evacuated. Staff were allowed back into the factory and the emergency services were not required to attend.”