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Waitrose has ranked last in a Which? Test looking at fresh food shelf life – while budget-friendly Asda has come out on top.

A new investigation by the consumer champion has revealed a major difference in how much time shoppers are given to use fresh and perishable food depending on where they shop.

There's nothing quite like the convenience of having your weekly groceries turn up on the doorstep – no navigating busy aisles, enduring winding queues and dragging heavy bags home.

But this modern-day convenience can come with an unwelcome surprise when you open the bags to find a sad-looking head of broccoli, bruised brown nectarines or a pack of raw chicken that has just a day or two left before it needs eating.

And those who are loyal to their supermarket of preference could be getting short-dated food more often than they realise.

Which? sent 12 mystery shoppers to place identical online orders with Asda, Morrisons, Ocado, Sainsbury's, Tesco and Waitrose over a two-week period.

They then calculated the number of full hours remaining between each delivery and midnight on the product's use-by date, giving an average shelf life for each supermarket.

A new Which? study has revealed a major difference in how much time shoppers are given to use fresh and perishable food depending on where they shop - with Waitrose (pictured) found to have the shortest average shelf life

Waitrose surprisingly came bottom of the six major supermarkets tested, while Asda delivered the freshest groceries of all.

Fresh food delivered by Waitrose was found to have an average of just 7.7 days left to use.

The high-end supermarket performed particularly poorly for a number of products, including scones, bread, fresh pasta sauce, fresh tagliatelle, hummus and pork sausages.

In one notably striking example, two packs of Waitrose beef mince and a pack of chicken thighs arrived with a use-by date just one day after delivery.

The study shows Tesco did not fare much better, with an average shelf life of just 8.8 days.

One shopper received fresh pasta sauce and pork sausages with just 3.4 days left before they expired – considerably less than Tesco's own online guidance suggests.

The supermarket states customers ordering fresh pasta sauce should expect at least a week of shelf life, while its guidance says shoppers should have at least five days to use its pork sausages.

Sainsbury's was a short step above, with an average shelf life of 10.2 days, although there were some disappointments.

As for Ocado, it delivered mostly long-lasting products, including two packs of honey roast ham which had more than 20 days left before their use-by dates

The biggest winner was Asda, which delivered the freshest groceries overall. Five shoppers received beef mince with at least 18 days remaining before its use-by date

Three items – sweetcorn and two packs of basil – had a best-before date on the day they arrived, while a pack of chicken thighs had a use-by date the next day.

As for Ocado, it delivered mostly long-lasting products, including two packs of honey roast ham which had more than 20 days left before their use-by dates.

However, one shopper was sent basil that was technically in date but described the herbs as black and wilted.

Morrisons also performed well overall, but one raspberry trifle that had been substituted had less than four hours left before it expired.

Another shopper received an opened pot of pineapple that had leaked across other groceries.

The biggest winner was Asda, which delivered the freshest groceries overall.

Five shoppers received beef mince with at least 18 days remaining before its use-by date, while one pack of cod had seven days left.

A tomato and mascarpone pasta sauce ordered by Which? from Asda also had an average of 33.6 days remaining, compared with just 12.2 days for the same product bought from Waitrose – despite the Waitrose version costing 23p more.

The investigation also found that some products were repeatedly more likely to disappoint shoppers, with several reporting that pre-cut carrots from different supermarkets looked 'slimy', 'wet' or 'manky'.

The study comes as households continue to feel the pinch on their grocery budgets, making short-dated food a frustrating aspect for those who are trying to plan meals and avoid waste.

A Which? survey further found that 16 per cent of people who had experienced problems with their most recent online supermarket delivery said receiving perishable items with a very short shelf life was their ultimate frustration.

Reena Sewraz, Which? retail editor, said: 'When you pay for a supermarket delivery, you expect your fresh food to have a reasonable amount of time left on it.

'Our investigation found a striking difference between supermarkets, with some shoppers getting several days’ less time to use their groceries than others – and in some cases, just hours.

'It’s particularly hard to swallow when you’re paying premium prices but getting food with a much shorter shelf life.

'Supermarkets need to make sure their freshness promises actually deliver, so shoppers aren’t left having to change their meal plans, rush to use food or throw away groceries they’ve paid for.'