Findus has said that it was not invited to today's meeting with environment secretary Owen Paterson at Department for Environment, Food and Rural Affairs (Defra) about the horsemeat crisis.
Defra said that four of the 14 groups and retailers invited to horsemeat summit did not turn up.
They were M&S, Waitrose, Lidl and the Chilled Food Association.
A leading food scientist says the rule change that sparked the horsemeat beef scandal affected lamb products too, and they should be tested.
Retailers and the Food Standards Agency held an emergency meeting today to decide how to proceed with the horsemeat scandal.
The government has called an emergency meeting with retailers and the Food Standards Agency to discuss the horsemeat scandal.