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Tesco has revealed more than two thirds of salad grown for bags is thrown out. What can be done to prolong the life of food, asks Kathryn Westcott.

Forty per cent of apples and just under half of bakery items are also uneaten. So what kitchen tricks can help?

Dampen the outside of a loaf of bread that has gone hard with a little bit of water and pop it in a hot oven - about 180C (350F) - for about five or 10 minutes, says food writer Stefan Gates. Baguettes that are past their best are regularly cut into 1/2cm slices in the Gates' household and put into a warm oven (about 50C, 120F) for about 15 to 20 minutes. "We use them as a form of biscuit for cheese," says Gates. "They can be stored in a sealed plastic bag."

Limp biscuits can also be revived in the oven. Five minutes in a hot oven (180C, 350F) should do it. This new-found freshness won't last, though.

There are a number of tricks for keeping lettuce fresh and crisp. Lovefoodhatewaste.com, external suggests separating the leaves and storing them in a bowl of water in the fridge. Replace the water every couple of days.

Culinary tips and tricks blog , however, favours the "bath towel method", which entails cutting up greens, washing them, putting them in a salad spinner and spreading them on a clean towel to air dry for a few hours. Roll up the towel with the greens inside and secure with rubber bands. Just take out what you need for that day and bundle it up again, it suggests.

"Packet lettuce is preserved in gas and once it starts to go off, nothing will revive it," says chef Clarissa Dickson Wright. But she says a Cos or Little Gem can be revived by leaving in really cold water - maybe with some ice cubes in - and leaving overnight." Otherwise, she says, make lettuce soup. "Fry some onion and garlic, add stock and toss in the lettuce leaves. Top with croutons made from your old bread," she says.

Cucumber that has gone limp can be revived by chopping off the end and standing it in cold water, according to Love Food Hate Waste. It also suggests freezing cheese and milk. Grate the cheese first and then put it straight from the freezer into sauces or lasagnes, etc.

Dickson Wright also suggests freezing bananas for ice cream. Peel them first then whizz them in a food processor.

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