Sainsbury's is opening a new front in the own label versus brand war with the launch of a major in-store sampling spree as part of its Switch and Save campaign.

The two-week Taste Test Challenge has been introduced to 400 stores and invites shoppers to sample items such as Rose's Lime Cordial and Kellogg's Rice Krispies and compare them to the retailer's own-label equivalents.

Shoppers are then encouraged to place a token into one of two corresponding tubes to indicate their favourite product.

The initiative is being backed by a marketing campaign that includes a TV ad featuring ice cream, high-juice squashes and yoghurts. "We are confident in the quality of our products so we're happy to carry out this test in such a public way," said Sainsbury's customer director Gwyn Burr. "We have spent so much time improving our entire range that we believe customers will vote for Sainsbury's own brand time and time again."

Branded suppliers such as Kellogg's and Weetabix said they were up to the challenge and claimed they were confident their sales would not suffer. "We welcome competition, it makes us better," said a Kellogg's spokeswoman. "We think shoppers may have already voted with their feet. Switch and Save PoS has been placed on brands, including ours, for about a year and during this year we've continued to grow in Sainsbury's."

Switch and Save provoked outrage on its launch last September, one supplier describing it as a deliberate attempt to damage his business.