Greencore is talking with private equity firms with a view to securing support for a new offer for Northern Foods, according to sources familiar with the situation.

Northern Foods, which makes Fox’s biscuits and Goodfella’s pizza, agreed last month to back a bid worth 73p per share from businessman Ranjit Boparan, valuing the business at £342 million ($552 million) and trumping an all-share offer from Greencore.

Greencore has said it is reviewing its options and sources said it is now seeking a private equity partner to part-fund a higher offer, possibly including a cash element.

Greencore on Wednesday appointed ex-Cadbury executive Alan Williams as its finance director, leading to speculation it could be giving up on the deal as its original offer had proposed Northern Foods Finance Director Simon Herrick would take the same role in the merged entity.