Cutlery which delivers an electric shock to change the taste of food could help cut down salt in fast food, researchers have said.

Scientists have developed a pair of chopsticks, that can make food taste saltier, sour or bitter without the need for extra seasoning.

They are also working on a spoon and fork that could make food taste spicier or sweeter.

This "digital seasoning" technology could allow diners to tinker with the taste of their food as they eat so it suits them.

It could also help food manufacturers and restaurants to reduce the amount of salt they put into food without compromising taste.

The utensils work by delivering pulses of electricity to the tip of the tongue to stimulate the taste buds.

Dr Nimesha Ranasinghe, an assistant professor of computer science at the University of Maine who led the work on the electric cutlery, said:

"This technology is aimed at overlaying a virtual taste sensation. Depending on the food or beverage, it will augment the flavor.

"For example, when we eat mashed potato by applying an additional layer of electric salt, the overall flavor is enhanced."

Some Chinese takeaway food and ready meals were recently found to contain up to 11 times more salt than a bag of crisps - more than half an adults daily allowance. Salt is known to be linked to serious health problems like heart disease and stroke.