Employees at Princes' production plant in Bradford have been threatened with the transfer of jobs abroad after they took part in strike action.
Staff at the Princes Food site in Tong walked out for 12 days earlier this month along with colleagues at other factories around the country.
The chairman of the company's board of directors has now said that production could move to facilities overseas if more strikes take place next month in the row over pay.
Angelo Mastrolia, the board chair, said continuing industrial action could have a "hugely detrimental impact" on union and non-union members and the firm is facing increasing costs, including the rise in employer National Insurance contributions.
"Should Unite confirm the strike schedule for February, Princes will be forced to withdraw the three per cent offer.
"Furthermore, we will be compelled to transfer part of our branded production to other facilities, including those abroad, and if the strike action continues, this will likely become a necessary choice for the future, which could mean a need to reduce jobs at our UK sites.
"This is a very real risk, which benefits neither the workers nor the company," BBC quoted Mastrolia as saying.
Princes Food said it has had discussions with the union for several months and had "tabled an above inflation pay rise" of three per cent.
Princes Group is known for creating Branston and its own brands of jars and tins of meat and fish.
The Tong site has around 400 workers and eight production lines for dilutes, carbonates and ready-to-drink products including the Capri-Sun brand.
There are 185 Unite members at the Bradford factory.
Trade union Unite said its members had been told that a pay offer agreed with the site's previous owners had been revoked by Italian conglomerate Newlat.
Unite general secretary Sharon Graham said: "If Princes thinks its threats will weaken workers' resolve it has another thing coming. This is appalling behaviour from a shameful company.
"First it pulled the rug from under our members by reneging on a pay deal and now it is threatening their jobs with these union-busting tactics.
"Unite won't stand for such tactics and will be backing our members every step of the way in their dispute."
Two further strike days are planned at that site on 3 and 4 February as part of wider industrial action at sites in Long Sutton in Lincolnshire, Wisbech, Glasgow and Cardiff.
