A woman in a town near Naples got an unwelcome surprise when she bought a sack of potatoes at a nearby market, put them into water to peel and discovered one of them was a hand grenade apparently left over from World War II.

Olga Mauriello had put the potatoes in a vat of water and had just begun peeling them Tuesday when she found the explosive, covered in dirt, police said Wednesday.

An alarmed Mauriello, 74, called neighbors, who in turn called police.

Officers detonated the grenade in a park on Wednesday, state police said.

The grenade was believed to have traveled with the potatoes from France, the ANSA news agency reported.