In normal conditions, bread will go mouldy in around 10 days.
But an American company called Microzap says it has developed a technique that will keep the bread mould free for two months.
At its laboratory on the campus of Texas Tech University in Lubbock, chief executive Don Stull showed off the long, metallic microwave device that resembles an industrial production line. Originally designed to kill bacteria such as MRSA and salmonella, the researchers discovered it could kill the mould spores in bread in around 10 seconds.
"We treated a slice of bread in the device, we then checked the mould that was in that bread over time against a control, " he explained.
"And at 60 days it had the same mould content as it had when it came out of the oven."