(CNN) The US Food and Drug Administration has issued a warning letter to the Jimmy John's sandwich chain, saying certain vegetables it served were implicated in five outbreaks of E. coli or salmonella in the past seven years.

The letter accuses the chain of engaging in a pattern of receiving and selling "adulterated fresh produce, specifically clover sprouts and cucumbers."

"Jimmy John's restaurants have been implicated in multiple outbreaks that have spanned the past seven years and impacted consumers in no fewer than 17 states," FDA Deputy Commissioner Frank Yiannas said in a news release Tuesday.

"Jimmy John's has not demonstrated implementation of long-term sustainable corrections to its supply chain to assure the safety of ingredients used in its products," he said.

The restaurant chain has removed sprouts from all its locations until further notice, Jimmy John's president James North told CNN on Tuesday.

Read More