London: Having a two-week-old sandwich for breakfast may no longer be a terrible experience, as scientists have developed a new packaging technique which they say keeps the food fresh inside for a longer period.
The secret to stopping the food going off is the process of gas flushing in which oxygen in the packaging is replaced by CO2 and nitrogen, the researchers said.
Another trick, they said, is to mix the main ingredients in a slightly more acidic mayonnaise, which also stops the fillings from deteriorating. Highly perishable ingredients such as lettuce and tomatoes are not used.
"The product is as fresh on day 14 as it is on day one," Ray Boggiano, the man behind the technique, said.
He said: "The science is not new. It's all about using a protective atmosphere in the packaging.”
"It's the same technology that is used in packaged sliced meats. That's the basis."
Booker, the leading food and drink wholesaler in the UK, is about to start supplying the special sandwiches to convenience stores and corner shops - bucking the trend by food producers to emphasise freshness.
The products are likely to be sold for the relatively low price of 1.49 pounds, the report said.
"We've tested them thoroughly and they are nice to eat," added Boggiano, a food technologist who has spent almost a year developing the special sandwich.
Steve Foxil at Booker said: "They are ideal to reduce retailers' wastage."
However, nutritionist Dr Carina Norris said that the long shelf life may come at the cost of nutritional value.
"Fresh is always best, you should always aim for the freshest possible ingredients in everything you eat. It may be safe to eat, but nutrients could be lost in the ingredients over those 14 days," she said.