About two million tubs of Clover are being recalled after the manufacturer found the spread had been contaminated with mould.
The company has recalled Clover tubs from supermarket shelves
Dairy Crest has asked consumers to return tubs sitting in their fridges after 17 people complained of feeling sick after eating the spread.
It fears several hundred tubs have been accidentally mixed with a mould found in blue cheese such as Stilton.
Production has been stopped at its factory in Telford, Shropshire.
It said production would not restart until the problem had been resolved.
A company spokesman said: "As a responsible manufacturer we are recalling all tubs. It's impossible to know exactly what the number of tubs affected is."
'Blue cheese flavour'
He added: "Some mould got into the manufacturing process and into the product which has led to this situation where the product goes off before the end of the shelf life.
"When people are biting in Clover, they are getting a sometimes strong and sometimes unpleasant blue cheese flavour."
The spokesman added that the factory did not produce blue cheese and it was unknown where the mould originated from.
All sizes of tubs are affected as well as all best before dates up to 10 August inclusive.
Customers have been advised to dispose of the contents and keep the lid to claim a refund.