Multibillion-dollar retail giant Kroger Company defended its proposed takeover of rival Albertsons Companies, Inc. by highlighting its partnership with a blueberry grower that hired a labor contractor accused of orchestrating one of the largest human trafficking rings in modern US history.

Though the blueberry grower in question, Southern Press and Packing, is one of many suppliers that work with the grocery giant, the situation spotlights merger opponents’ claims that Kroger has failed to guarantee minimum standards for workers in its supply chain — a situation they say could worsen if the company is allowed to grow exponentially larger.

“As it is, Kroger is not doing what they should as a very powerful corporation,” said Lupe Gonzalo, a staff member for the farmworker-led human rights group the Coalition of Immokalee Workers (CIW), which has helped expose human trafficking cases involving more than 1,200 migrant workers. “Imagine them as an even more powerful company [and] not using that power to grant human rights to workers in their supply chain.”