Scotland Yard said that Michael Norman, 51, of Wreningham, Norfolk, and Alexander Taylor, also 51, of Yeovil, Somerset, faced three charges of threatening to contaminate food.
They were arrested on Thursday at a service station on the M4 near Bristol after a major police operation involving officers from Scotland Yard's international and organised crime branch.
The two men are charged with making demands with menaces of pounds 4,930,000 from Sainsbury, pounds 4,370,000 from Tesco and pounds 3,120,000 from Safeway.
The police operation codenamed Shank, involving about 50 officers, was set up several weeks ago after blackmail demands were made. Scotland Yard said that there was no danger to the public at any stage.