Union officials are meeting workers at the Birds Eye plant in Hull after concerns were raised about the company's future in Britain.
The meeting comes after workers at the Grimsby factory learned their factory was due to close.
Now officers at the GMB union want Birds Eye to clarify the situation for all their staff.
The company has said it is looking at all the possibilities as part of a review launched in November.
The Grimsby workers discovered the news about their plant's closure in a document which also revealed there could be job losses at the Hull site.
The finding of the review is overdue and that has prompted further concern that closure of the sites, rather than sale or investment, could be the most likely outcome.