The U.S. Food and Drug Administration (FDA) says sales of romaine lettuce grown in areas deemed to be safe can now resume, as long as the product is labeled with a harvest date and location.

In a Nov. 26 announcement, FDA Commissioner Scott Gottlieb also said that the E. coli outbreak that came to light last week has now led to 43 illnesses across 12 U.S. states, as well as 22 illnesses in Canada.

Gottlieb said he believes that romaine lettuce associated with the outbreak comes from areas of California that grow romaine lettuce over the summer months and that the outbreak appears to be related to “end of season” romaine lettuce harvested from these areas.

"The involved areas include the Central Coast growing regions of central and northern California," he said.

The FDA is continuing tracebacks of romaine from locations where impacted consumers purchased or consumed the product before they became ill.

"Based on further discussions with the leafy greens industry and with agricultural authorities, we have begun to narrow the location in which we believe the contaminated romaine in the current outbreak was grown," he said.

"At the time of the outbreak, the vast majority of the romaine on the market was being grown in the Central Coast region of California. Since then, harvesting of romaine lettuce from this region has ended for the year.

"Growing and harvesting of romaine lettuce is now shifting to the winter growing regions of the U.S., which include mainly the California desert region of the Imperial Valley, the desert region of Arizona in and around Yuma, and Florida."

Gottlieb added the FDA believes it was critically important to have a “clean break” in the romaine supply available to consumers in the U.S. in order to purge the market of potentially contaminated romaine lettuce related to the current outbreak. 

"This appears to have been accomplished through the market withdrawal request of Nov. 20, 2018," he said.

Based on discussions with major producers and distributors, romaine lettuce entering the market will now be labeled with a harvest location and a harvest date, said a new FDA advisory. 

Romaine lettuce entering the market can also be labeled as being hydroponically or greenhouse grown.

"If it does not have this information, you should not eat or use it," said the advisory.

"If consumers, retailers, and food service facilities are unable to identify that romaine lettuce products are not affected – which means determining that the products were grown outside the California regions that appear to be implicated in the current outbreak investigation -- we urge that these products not be purchased, or if purchased, be discarded or returned to the place of purchase."