( Courtesy Bonduelle Fresh Americas )

(UPDATED) The Food and Drug Administration is investigating an eight-state outbreak of E. coli, and although a Ready Pac brand salad was linked to cases in Maryland, no one who has gotten sick in other states said they ate that brand of salad.

The FDA has identified farms in Salinas, Calif., that possibly grew the romaine used in the salads and "is deploying investigators to the farms in question to determine the source and extent of the contamination," according to a Nov. 20 notice from the FDA on the outbreak. 

Maryland Department of Health officials on Nov. 15 reported they believed seven cases of E. coli were from consumption of Ready Pac Bistro Bowl Chicken Caesar Salads purchased at different Sam’s Clubs in Maryland. The FDA and Centers for Disease Control and Prevention are advising consumers not to eat that product with best-by dates of Oct. 31. According to the Maryland department and the CDC, patients reported eating the salad.

Yet the Nov. 20 update from the FDA reports that while E. coli was found on romaine in an unopened Ready Pac Bistro Bowl Chicken Caesar Salad, the agency is not yet certain that it's the cause of the illnesses in Maryland. Testing on the salad continues.

"Preliminary information indicates that romaine lettuce used in the product that tested positive was harvested in mid-October and is no longer within current expiration dates," according to the FDA. "To date, the food sample has not yet been definitively linked to the Maryland cases or other E. coli O157 illnesses in the multi-state outbreak. (Whole genome sequencing) analysis is currently underway for this sample to determine if it is closely related genetically to the E. coli found in people in this outbreak.

Also on Nov. 20, Bonduelle Fresh Americas, which markets the Ready Pac brand, released a statement that the Maryland agency, the CDC and the FDA have been listing the wrong product.in their public health notices. The product sold in Maryland, according to Bonduelle, is Ready Pac Foods Bistro Chicken Raised Without Antibiotics Caesar Salad, which is a two-count salad available at Sam's Clubs locations.

The lot number is 255406963 and Universal Product Code is 7774527249, according to the company.

"We continue to work with all regulatory agencies to trace the origin of this contamination as quickly as possible to reduce potential impacts to consumers," according to Bonduelle's statement.

The company did not issue a recall; by the time the illnesses were reported, the best-by date of Oct. 31 was more than two week past.

"At Bonduelle Fresh Americas, home of the Ready Pac Foods brand, the safety and quality of our products and the well-being of our consumers are our top priorities," according to the Bonduelle statement. "We rigorously test all of our leafy greens (including romaine) and did not have any positive test results for E. coli O157:H7 during this timeframe."

According to the CDC, E. coli illnesses are also in Arizona, California, Colorado, Idaho, Montana, Washington, and Wisconsin

In Wisconsin, 20 cases, including three children, were reported by the Wisconsin Department of Health Services, and Maryland had reported seven cases. The FDA and CDC counts are lower, apparently, as the agencies find common links and genetic matches to the pathogen.

Media reports have quoted Larry Lutwick, an infectious disease specialist at the Mayo Clinic in Eau Claire, Wis., who said there are at least three E. coli cases at the facility, two of which reported they suspect a “salad or salad ingredient.” Health officials have not publicly confirmed that.

Wisconsin state officials reported seeing a “significant increase” in E. coli cases on Nov. 13, reporting 20 cases on Nov. 15. The Maryland Department of Health announced its investigation into seven cases on Nov. 18, naming the Ready Pac brand salad as the common food item eaten by all patients.

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Maryland: E. coli related to romaine in Ready Pac salad

As romaine problems continue, FDA takes closer look

FDA: No ‘actionable information’ in recent E. coli outbreak