A coffee farm in Brazil certified by Starbucks was raided for forcing workers to live and work in conditions officials called similar to slavery.

Officials in Brazil raided a coffee plantation and rescued 18 workers who they say were laboring in conditions akin to modern-day slavery. The farm called Córrego das Almas, in the southeastern state of Minais Gerais, held two prestigious certifications, one from Starbucks and another from a sustainable farming certification organization in the Netherlands.

According to Mongabay and Repórter Brasil who broke the story, upon entering the farm there is a sign that reads “No slave or forced labor is allowed.” Yet when investigators raided the plantation, they found workers living in degrading conditions and substandard housing without sewage or drinking water which they called analogous to slavery.

The workers lived in collective housing in conditions that put workers’ health at risk. Workers told investigators that dead bats were often found in the water containers that they were told to use for drinking and eating, the containers were uncovered.

“There were lots of bats and mice. We’d buy food and the mice would eat it. Then we had to buy it again,” said one of the rescued workers.

Wages for employees were also rigged unfairly, according to accounts payable reports inspectors found.

“We weren’t paid for holidays, Sundays, nothing. And we worked from Monday to Saturday with no record of the hours. During the week, we would start at 6 am and only stop at 5 pm,” says another former employee rescued from the farm.

“We’d harvest and they’d leave it [the beans] there to be weighed the next day. When we arrived there, the coffee was gone. And then we were humiliated: we complained and they laughed in our faces,” said a rescued worker.

“I’ve always harvested coffee, and I’ve never been through something like that in my life. I wasn’t even able to send money home,” adds another.

The farm holds one of the most prestigious coffee sustainable farming certifications known as the UTZ seal in addition to Starbucks’ C.A.F.E. Practices certification. Starbucks, however, said they had not bought coffee from the farm in years. Both companies said they would review the certifications – certifications that are meant to certify that farmers’ practice ethical farming and good labor practices.

The farm has 151 employees, cares for 3 million coffee trees and raises cattle. The property owner released a statement expressing “shock” upon learning of the raid since slave labor is not the company’s “work philosophy.”

“Our farm has been operating in the coffee market for many years and has always sought to comply with all legal requirements, that includes obtaining all certifications, licenses and awards whose requirements are extremely strict,” the statement read.

In another town in the same state, investigators rescued another 15 workers from similar slave labor conditions at a coffee plantation.

Workers’ rights organizations in the area said it is not uncommon for certified farms to have employees work in such conditions.

“This is not the first or second time, and it will not be the last time a certified farm is charged with employing slave labor and violating labor rights,” said Jorge Ferreira dos Santos, head of the Coordination of Rural Employers of Minas Gerais (Articulação dos Empregadores Rurais de Minas Gerais, Adere-MG) and who accompanied the inspectors. “The certification system is weak and not transparent,” he said.