It’s impossible to judge the success of GIZ’s efforts, or any Ferrero’s programs, because the company will not share any information about them, citing “restrictions under national privacy laws.”

Ms. Mittal of the Fair Labor Association said Ferrero would take the organization’s phone calls and participate in panel discussions about labor issues. It just won’t disclose where and how it buys hazelnuts.

“We know nothing about the findings of the programs they have in place,” she said. “We know nothing about the difference between certified and uncertified farms. We have no clue.”

The Fair Labor Association has a far better view of Nestlé’s supply chain because it collaborated with it on a 31-month pilot program sponsored by the United States Department of Labor. At best, these efforts are a modest start, as Nestlé found in a 2017 survey published on its website.

More than 72 percent of workers reported that they had barely enough money to get by. Ninety-nine percent said they worked seven days a week. Child labor issues, the company stated, have “deteriorated in the last year” because of the war in Syria. Nestlé declined to comment for this article.

For refugees, Turkish agriculture is both a lifeline and a continuing trial. In the five years since he left his homeland, Mr. Ibrahim, the onetime taxi driver, has developed a new sense of what constitutes misfortune.

“We are lucky,” he said. “We can survive here. We will never be thieves. We will never have to beg on the streets.”