Now, a wrapping that will tell you when foods going off

The smart plastic packaging detects when meat, fish or salad leaves have passed their use-by date or have been left out of the fridge for too long; it also alerts householders if sealed packaging has been broken or damaged, putting contents at risk, the `Daily Mail` reported.

The British scientists behind the intelligent wrap believe it will reduce unnecessary household waste and help cut tons of food being thrown away, and will also help people uncertain about best-before and use-by dates on food.

Previously, researchers have developed indicator labels which are inserted into food packaging. But, the new plastic is designed to be part of the wrapping itself.

It works with food such as meat, fish or salad that has been sealed in a "modified atmosphere"- where levels of oxygen are reduced and replaced with inert nitrogen or carbon dioxide gases to slow natural decay.

The new plastic is designed to change colour if levels of oxygen rise above a predetermined level. It also responds to chemical changes triggered by food spoiling.

Professor Andrew Mills, who is leading the research at Strathclyde University, was quoted as saying, "At the moment we throw out far too much food, which is environmentally and economically damaging.

"We hope this will reduce the risk of people eating food that is no longer fit for consumption and help prevent unnecessary waste of food.