IN the coming weeks almost every member of staff at J Sainsbury will receive a pack containing tuna, coriander, chilli and soy sauce.

Chief executive Justin King hopes that the goodie bag will encourage his staff to try Jamie Oliver’s marinated tuna, a recipe that is part of a Sainsbury advertising campaign to encourage us all to “try something new today”.

Sainsbury’s staff are not the only ones who are experimenting in the kitchen. We are becoming a nation of “foodies”, increasingly obsessed with what we eat. We may not make chicken tikka masala ourselves, but we certainly want to know what goes into it. Growing numbers of us are also interested in where the chicken was raised and even whether its short life was “happy”.

Two of the top ten selling books this Christmas were written by celebrity chefs and millions tune in to watch the likes of Hugh Fearnley-Whittingstall lecture the nation on animal husbandry and country cooking.

When Oliver suggested grating nutmeg on spaghetti bolognese in a Sainsbury ad, sales soared 300%.

Sheila Dillon, presenter of Radio 4’s Food Programme, believes a revolution is taking place. “People have begun to grasp that food matters. You know that the culture is changing when even McDonald’s is buying grass-fed beef,” she said.

“Foodies” now make up 58% of shoppers in Britain, compared with 44% in France and 32% in Germany, according to research carried out by the management consultancy McKinsey for IGD, a think tank.

The growing interest in premium food — and that we are prepared to pay for it — has helped deliver bumper Christmas sales at Sainsbury, Marks & Spencer, Waitrose and Tesco.

When Justin King arrived at a troubled Sainsbury in 2004 he put quality food at the centre of his recovery plan — “making Sainsbury great again”.

“The whole legacy was as a quality-food business,” said King. “Customers had stuck with us despite all the problems because we were still better at quality, fresh food.”

As long ago as the 1980s Sainsbury was boasting about how many more oranges went into its juice than its rivals’ products. Apart from the design, the ad would not look out of place today.

Sainsbury’s 1990s slogan, “good food costs less” has been replaced internally with “great food, fair prices” and King believes the focus on food differentiates Sainsbury from rivals that look increasingly to non-food area to deliver growth.

The strategy appears to be paying dividends, with a 5.2% rise in like-for-like sales in the crucial third quarter.