(Independent) - Paola Clemente, a 49-year-old mother of three, rose at 2am, on 13 July as she usually did. She took the coach from her little town of San Giorgio Jonico to arrive at the vineyard near Andria after 5am. But she never came home.

Despite complaining that she felt unwell on the way to work, the man who hired her reportedly told her that discomfort would pass. In fact she died that day, her heart apparently giving out in the fields where she picked grapes in 38C heat for £1.50 per hour.

Her death has put the spotlight on the plight of southern Italy’s fruit pickers, with tens of thousands of poor, unskilled female labourers and migrants working in often illegal conditions, and doing punishing hours for a pittance.

In Puglia, the beautiful heel of the Italian boot where five-star hotels and luxury villas cater to northern Europe’s middle classes, something akin to modern slavery is supplying the holidaymakers with the wine and food they enjoy at their dinner table. And many of the fruits of the region make their way as far as the British supermarkets.

Another Italian worker from Ms Clemente’s home town suffered a heart attack in the same fields at the end of July. A week after Ms Clemente’s death, a 47-year-old Sudanese man, Mohammed, died near Lecce, in similar circumstances, and not longer after him a Tunisian worker perished.

“To die working in a field of grapes is to immediately become a phantasm, with no news emerging for weeks,” said Peppino Deleonardis, the regional secretary of the Flai-Cgil farm workers union. “Paola would not have expected to die like that, after 15 years of working in the fields from dawn until after dark.”

On Wednesday last week Ciro Grassi, from Taranto, who is understood to have recruited Ms Clemente and the other workers and took them to the fields to pick grapes, was placed under investigation by magistrates, suspected of homicide and failure to come to the aid of a sick person.

Prosecutors have ordered Ms Clemente’s body be exhumed and an autopsy is due to take place this week.

Ms Clemente’s son Marco was still too upset to speak about her death. But Vito Miccolis, one of the high-powered legal team paid for by the Flai-Cgil union, told The Independent that her family was determined to find out the truth about how she died. Details are sketchy so far.

“The biggest challenge is changing people’s attitudes here,” said Mr Miccolis. “People here working for this sort of money in these sort of conditions is normal.

“Many of the pickers are union members. The problem is that people are frightened about losing their jobs. They need this money. Some places in Puglia use Romanians and Albanians – and they’re treated even worse,” he said.

The chief prosecutor of Trani, Carlo Maria Capristo, said he aimed to bring justice to the victims and their families, but he added: “On the phenomenon of illegal hiring there is a wall of silence. People prefer to earn a little money instead of collaborating with our inquiries aimed at eradicating the problem.”

Ms Clemente’s husband, Stefano Arcuri, explained why his wife worked in such conditions when a journalist from La Repubblica last week suggested to him that they amounted to “slavery”. “It was secure money,” Mr Arcuri said. “Given the way things are in Italy, it was vital income for Paola and us. It enabled us to survive.”