Asda, the UK arm of retail giant Wal-Mart, has slammed claims that food bought online in the UK is less fresh than products bought in store.

A study by consumer group Which? claimed that, on average, the best-before dates in stores were more than a day later than those for the same products bought online.

Which? said the findings had confirmed its assertion earlier this year that only around four out of ten Asda and Sainsbury's shoppers believed use-by dates on groceries from their most recent online shop were as extended as those they would have seen in store.

However, Asda said the report was "seriously flawed". "Which? only shopped once in each store and once online, and even then the difference they found was marginal," a spokesperson told just-food.

"It's daft to think that every online retailer in the land is deliberately trying to give their online customers a worse deal than those who shop in store. Particularly when products bought online are picked off the exact same shelves in store."