Unite has urged talks with Heinz, on the back of the company's "devastating" plans to cut 250 jobs across the UK.
The plans were unveiled by the manufacturer earlier this week, claiming that they were a part of its ongoing measures to cut costs.
Senior members of the company have reportedly said that cutting costs is an essential part of ensuring that the company's transition from a publically listed company to a private firm is a smooth as possible.
But union Unite has claimed that the cuts would be "devastating" for workers and their families.
Unite's national officer for the food sector Rhys McCarthy said: "The news that Heinz is proposing nearly 250 job cuts in the UK is devastating and will, no doubt, have a huge impact on our members and their families.
“A nearly ten per cent reduction in UK staff is savage, unnecessary and is putting profits before people.
“Ruthless cost cutting to maximise returns is the hallmark of pirate privateers.
“We are now seeing it happening at Heinz which was bought out by Warren Buffett's Berkshire Hathaway and 3G Capital venture capitalists for £18 billion at the beginning of the year."
Unite also said that it was concerned by the fact that it had only found out about the proposals through the media, which it said had demonstrated a lack of respect for the union and its members.
Heinz employs 2,600 employees across the UK with factories in Hayes, Wigan, Kendal, Telford, Westwick and Worcester.
The company said in a statement that it regretted the impact the cuts would have on workers but said it would "strengthen and leverage" its status on a global scale.
The decision comes after doubts were expressed in June over the viability of the company's factory in Kendal, an announcement came after the loss of 45 jobs across its production and management divisions.
The production of baby milk was then moved from Kendal to a factory in New Zealand, which is run by the dairy giant, Fonterra.