The FDA and Centers for Disease Control and Prevention said they had narrowed down the suspect lettuce to lettuce harvested in northern and central California. They still don’t have enough information to name a specific grower or distributor, but said consumers can begin to look for the popular lettuce again.
Last week, the CDC and FDA told people not to eat any romaine lettuce at all and said stores should take it off the shelves.
But, "over the Thanksgiving holiday, the FDA continued to investigate the outbreak. Our investigation at this point suggests 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," FDA commissioner Dr. Scott Gottlieb said in a statement.
Let our news meet your inbox. The news and stories that matters, delivered weekday mornings.
So people can eat some romaine confidently. “If you do not know where your romaine lettuce is from, do not eat it,” the CDC said in a statement.
“There is no recommendation for consumers or retailers to avoid using romaine lettuce that is certain to have been harvested from areas outside of the Central Coast growing regions of northern and central California,” the FDA added.
“For example, romaine lettuce harvested from areas that include, but are not limited to the desert growing region near Yuma, the California desert growing region near Imperial County and Riverside County, the state of Florida, and Mexico, does not appear to be related to the current outbreak. Additionally, there is no evidence hydroponically- and greenhouse-grown romaine is related to the current outbreak.”
There’s been a "clean break" from romaine, so product that could have been contaminated is probably gone from stores, Gottlieb said.
He said the FDA was working with the food industry to come up with better ways to label the origin of lettuce and other fresh produce. That will help identify the source of future food-borne outbreaks.
"Knowing the growing origin of produce will continue to play an important role in allowing consumers to avoid contaminated products and facilitating market withdrawals and tracebacks," Gottlieb said.
The FDA urged stores and distributors to label lettuce by origin.
“Based on discussions with producers and distributors, romaine lettuce entering the market will now be labeled with a harvest location and a harvest date or labeled as being hydroponically- or greenhouse-grown. If it does not have this information, you should not eat or use it," the FDA advised.
E. coli is normally harmless, but there is a strain called E. coli 0157:H7 that produces a compound called Shiga toxin that can make people very ill. The CDC says 16 people have been hospitalized in this outbreak and one has a serious kidney condition called hemolytic uremic syndrome.
This outbreak is linked to an outbreak one year ago that was not directly linked to romaine lettuce by U.S. authorities, but only to salad greens. Canadian authorities linked it to romaine at that time.
A separate outbreak of E. coli in romaine lettuce in the spring was traced to contaminated irrigation canal water in Yuma, Arizona.
Foodborne illnesses are very common. The CDC estimates that 48 million Americans get sick from a foodborne illness every year. Of them, 128,000 are hospitalized, and 3,000 die.
Maggie Fox is a senior writer for NBC News and TODAY, covering health policy, science, medical treatments and disease.