Naples - A 74-year-old Italian grandmother who bought a sack of potatoes at the her local market found a live grenade among the spuds.

"I found a bomb in the potatoes," Olga Mauriello said.

"I went to the market to buy some potatoes and that's where the bomb was. But this bomb was covered in dirt, and I put it in water and got all dirt off. And then I realised 'It's a bomb'!"

Police said the pine cone-shaped grenade, which had no pin and was still active, was the same type used by US soldiers in Europe in World War II.

Authorities believe the mix-up happened at a farm in France, where the grenade was plucked from the ground along with potatoes.

To the woman's relief, police and explosives experts in the small town of San Giorgio a Cremano, near Naples, recovered the grenade and safely detonated it on Wednesday.

But Mauriello was still shaking off her close brush with death. It didn't look like a potato and it was heavier than one.

But what if she had cooked it?

"If I hadn't felt its weight, I wouldn't even have realised that it was a bomb," she said.