Managers at the site had subsequently hidden product that still did not comply with recommendations, and this later ended up on supermarket shelves, according to the Mid Suffolk District Council.

The council brought charges against 2 Sisters after it found products had been given a 14-day shelf life — four more days than the Food Standards Agency (FSA) recommends for vacuum and modified atmosphere-packed chilled foods. The intent of the FSA recommendation is to minimize the risk of botulism developing in the packaging.

Following this discovery, the council issued a Remedial Action Notice ordering 2 Sisters to reduce the products' shelf life to 10 days, but a further inspection at a later date found 2 Sisters had reverted to 14 days.

The council said 2 Sisters managers at the Haughley Park facility had hidden "substantial amounts of product from investigating officers, some of which was later found in retail outlets by the environmental health team, who suspected they were not being given the full facts."

It added that the company took more than seven weeks to share production records, which it said demonstrated that large quantities were involved and put "a serious question over product traceability."

On 27 September the case was heard at Ipswich Crown Court, and 2 Sisters pleaded guilty to several offenses, including failing to comply with the council's remedial action notice and failing to have a suitable food safety management system in place. The firm was fined £112,500 and was ordered to pay the council costs of £41,000.

John Grayling, manager of food and safety services at Mid Suffolk and Barbergh district councils, said: "Someone in the organization was putting profit before food safety and it seems likely they were doing so because they thought it was what the company wanted."

A spokesperson for 2 Sisters said: "We deeply regret that what started as a genuine disagreement about the proper shelf life for certain products ended in a prosecution due to miscommunication within our organization, which resulted in a number of procedural oversights."

He added there was no safety risk with the products involved, but the firm should have gone further to enforce the remedial action notice. It also accepted that record keeping should have been amended and updated.

Earlier this year, it emerged that the Haughley Park site was set to close because of its age and condition.