ASDA are to investigate after a suspected spider egg sac was found on a banana.

John and Melanie Whitlock discovered the web-covered mass while unpacking the weekly shopping at Asda, Blackwood.

Mr Whitlock said: "I heard my wife shouting from the kitchen so I came in from the front room and saw what looks like a spider's egg sac on the banana," said Mr Whitlock, 39, of Priors Gate, Oakdale.

"It is about the size of a 10p piece and I can't imagine it being anything else."

He added: "My wife ran out of the room when she saw it because she is absolutely terrified of spiders. She doesn't know I've kept the banana with the egg sac on and she'll go crackers when she finds out I've still got it!"

The environmental health department of Caerphilly county borough council is also being told of the find.

A spokesman for Asda said: "We would need to send it off to be tested so we can find out exactly what it is."

The spokesman added that Asda's bananas go through a vigorous cleaning and inspection process, which any species of tropical spider was unlikely to survive.

There were incidents of spiders being found in bunches of supermarket grapes at Tesco stores in England last year, because of more organic farming methods.

In one Tesco store a shocked customer discovered a deadly black widow spider.