The labor union International Brotherhood of Teamsters has been holding nationwide protests at Chipotle locations this month, taking issue with one of the restaurant chain’s suppliers. The supplier at the focus of the demonstrations is California-based produce company Taylor Farms, which supplies tomatoes and peppers to Chipotle, according to Teamsters.

“Over the past five years, Taylor Farms has had more than 20 food recalls for problems such as Listeria, Salmonella and E. coli. In November 2015, Taylor Farms products containing celery and sold at Costco and other retail outlets were recalled for possible E. coli 0157:H7 contamination,” according to a Teamster news release. “At Taylor Farms’ plant in Tracy, Calif., the company has also committed safety and health violations and violations of laws that protect workers’ rights. Recently, the company settled extensive labor rights violations that involved payments of $267,000 to illegally terminated workers and a required posting in which the company promises to never again violate a long list of employee rights.”

The Teamsters protested at 12 Chipotle locations across the country, following 30 previous protests at Chipotle over the past several months.

Teamster Vice President Rome Aloise points the finger at Chipotle for allowing Taylor Farms to “have a total disregard for consumers’ and workers’ health and safety, as well as workers’ rights,” he said. “Chipotle claims to serve ‘Food With Integrity’, but where’s the integrity when it turns a blind eye to its supplier’s behavior? Chipotle must not cut and run – which would hurt Taylor Farms workers – it must carry out its social responsibility and demand Taylor Farms treat workers fairly and with respect.”

Taylor Farms has not released a statement addressing the protests.