If you’ve eaten a chocolate bar in the past year, you may have contributed to the world’s growing slavery program. Have a pair of Levi’s jeans? You’re mostly in the clear. Sporting a new pair of Sketchers? You may want to return them.

“There are so many invisible connections we have to slavery that we perpetuate without even knowing it,” said Brant Christopher, artist in residence for the anti-slavery organization Not For Sale. “We tell the story of what’s happening with human trafficking in the world today.”

Mr. Christopher and Not For Sale founder David Batstone will speak on Sunday at the Tabernacle in Oak Bluffs on the present day and very real issue of human trafficking and slavery across the world. Their campaign has brought them to seven different countries, and the Vineyard is their next stop; the evening is being sponsored by Faith MV church.

Pastor Jeff Winter is a member of the abolitionist faith network for Not For Sale. “I feel like we can be isolated on this Island and not be educated in the areas of great concern, one of them being the human trafficking issue,” Mr. Winter said. “I want people on this Island and vacationers to learn steps you can take on this Island to help remedy the issue.”

Not For Sale actively engages with 250,000 people to help end modern-day slavery. The Free2Work program focuses on the supply chain of products and gives letter grades to major manufacturers for their association with slavery. Levi’s Jeans received a B, a high rating, Hershey’s received a D+ and Sketchers received an F.

Free2Play allows athletes to become directly involved with their sports equipment through the use of a slavery map around the world.

“People are most surprised that it still exists,” Mr. Christopher said. “They thought it went away with Abraham Lincoln.” He said there are 27 million slaves in the world, 200,000 of them in the United States. Many work in restaurants, massage parlors, hotels, farms and brothels.

“It’s an invisible problem, that’s why people don’t know that it exists,” Mr. Christopher said. “It’s not something that’s paraded out there.”

The campaign started when the death of a 17-year-old girl who was a bonded slave in a restaurant in Berkeley, Calif., came to the attention of Mr. Batstone. He decided to do something about it, and three years later Not For Sale continues.

“We’re modern day abolitionists,” Mr. Christopher said. “The thing that separates Not For Sale from other organizations is that we are all about engagement. The last thing we want to do is come in and talk and have you leave without anything you can do about it.”

The two men hope to educate Vineyarders on what they can do to help end slavery. The nearest incidents of reported slavery in the area were in New Bedford, they said.

Mr. Winter said he hopes to bring together a group of people to continue the discussion of how Islanders can help. “I know people care about this issue. You can bring together all different people from all different faith divisions and band groups of people,” he said. “I want to be able to talk together about what we can do in a proactive way.”

The Not For Sale presentation is Sunday at 8 p.m. at the Tabernacle in Oak Bluffs.