Other leafy greens in the produce section, including spinach, may be missing from your grocery store soon—here's why.

Shoppers and retailers sprung into action last week when the CDC warned Americans to dispose of romaine lettuce due to another E. coli outbreak (the third one this year). Similar to an outbreak over the summer, a blanket federal ban has been put on romaine lettuce. But one industry expert says that the nature of this ban means that more than just romaine could be at risk for contamination.

Michael Droke is a partner at the international law firm Dorsey & Whitney who specializes in agricultural and cooperative law. In his career, he's worked extensively with agriculture titans and food manufacturers. Upon hearing of the CDC's blanket ban last week, Droke says that many retailers may have removed more than just romaine lettuce from shelves—and for good reason.

"A recall of this magnitude especially during the holiday week will impact not only romaine, but other leafy green vegetables such as spinach," Droke said. "Retailers will be pulling romaine and possibly all other lettuce/leafy greens from their shelves (a process called quarantining) until the source is found."

Droke says that nearly every major grocery chain pulled raw romaine lettuce almost immediately, within an hour of the CDC bulletin. Given the high-profile nature of the case, items containing romaine were also pulled that very same day. You may wonder why would retailers be worried about anything other than romaine—and what exactly is a retail quarantine?

"Retailers often call the process of pulling items off shelves ‘quarantining’ the product," Droke explains. "In some cases, retailers also remove related leafy green products due to perceived customer concerns. Regardless, customers afraid of infection will also stop buying other types of lettuce."

It's also true that E. coli bacteria can spread upon contact in many cases, the CDC reports, so if a grocery chain chose to stack romaine heads in direct contact with other nearby greens, there's a chance they removed those products to err on the safe side.

More on E. coli and how it affects romaine lettuce:

Droke also explained that, in some cases, retailers could be the one to remove all leafy greens out of fear of customer complaints.

"In some cases, retailers also remove related leafy green products due to perceived customer concerns," he said. "Many companies with products containing lettuce added notice or stickers stating that the product ‘does not contain romaine’ in order to retain customers."

This latest romaine outbreak comes amid news that Americans are experiencing more recalls and foodborne illnesses than ever. The CDC has issued 21 food warnings since January, making 2018 a record year for food scares within the last decade. With stats like this, coupled with the chance of cross-contamination, it makes sense that retailers may pull other greens off shelves.