Ashley May | USA TODAY

USA TODAY

The romaine lettuce responsible for an E. coli outbreak that sickened more than 30 people across multiple states likely originated in California, according to Food and Drug Administration commissioner Scott Gottlieb.

Gottlieb said Friday morning that the Golden State connection is based on observed "growing and harvesting patterns."

"New romaine from different growing regions, including Florida and Arizona, will soon be harvested," Gottlieb tweeted. "We’re working with growers and distributors on labeling produce for location and harvest date and possibly other ways of informing consumers that the product is 'post-purge'"

He also said the FDA is hoping to create a new labeling standard that would require companies to show where lettuce is from and when it is harvested.

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Two days before Thanksgiving, the Centers for Disease Control and Prevention issued a food safety alert saying 32 people across 11 states had become sick because of contaminated romaine lettuce. The CDC is advising people avoid romaine lettuce completely.

States affected by the outbreak include California (which had the highest number of cases — 10), Michigan, Connecticut, Illinois, Massachusetts, Maryland, New Hampshire, New Jersey, New York, Ohio and Wisconsin.