Almost 100 people have been infected in an outbreak involving romaine lettuce, and more cases are expected. Federal officials said today they have identified one grower’s romaine as the source of eight of the infections, but a tangled web of supply chain records has significantly slowed their investigation into the other illnesses.

The ongoing outbreak is the largest of its kind since the deadly 2006 E. coli outbreak traced to fresh spinach, public health officials said. There are at least two dozen romaine growers who are being reviewed as federal officials work to pinpoint the source of the current outbreak.

As of today, there are 98 confirmed cases across 22 states, up from the 84 cases reported Wednesday. All of the victims are infected with the same strain of E. coli O157: H7, and it is a particularly dangerous one, said CDC’s Robert Tauxe. Ten of the sick people have developed kidney failure, including three children.

More than half of the ill people, 46, have required hospitalization. The illness onset dates range from March 13 to April 20. 

The specific bacteria involved is referred to as an “STX2 only” form of E. coli O157: H7. It aggressively attacks blood vessels, particularly in the kidneys, digestive system and brain. 

No one should eat, serve or sell any form of romaine lettuce “under any circumstances” until further notice unless they can confirm is not from the Yuma, AZ, growing region, said Matt Wise, deputy branch chief for Outbreak Response at the Centers for Disease Control and Prevention. That warning is the same that the CDC posted April 20. Initially, only pre-chopped romaine was implicated.

Wise said the specific E. coli O157: H7 bacteria causing the illnesses is so dangerous that all people, not just the traditional high-risk groups, should avoid Yuma-grown romaine. 

Known and unknown
The CDC knows quite a bit about the confirmed victims, including the fact that 96 percent of those interviewed so far, 67 of 98, reported eating romaine during the week before they got sick. They know that all but eight of the 98 ate pre-chopped romaine from bagged or other packaged mixed salads and at restaurants.

The eight who consumed romaine from whole heads are inmates at a prison in Alaska that received the lettuce from Harrison Farm in Yuma, said Stic Harris, director of the FDA’s Coordinated Outbreak Response and evaluation Network. However, inspectors from the Food and Drug Administration have not yet visited the farm and have not been provided details such as the specific location of the field wher the implicated romaine was grown.

The FDA’s and CDC’s outbreak specialists discussed the ongoing public health threat involving romaine lettuce during a telephone news conference this afternoon.

Other than identifying the Yuma area in general and Harrison Farm in particular, FDA officials answered many of the media’s questions today with: “We don’t know yet.” That lack of knowledge is not for a lack of trying, according to FDA’s Harris.

The current federal law requires entities in the food supply chain to only maintain shipping and receiving records that are referred to as “one step forward, one step back.” That means every link, from growers to retailers and restaurants, don’t have to know wher fresh produce ultimately goes or comes from.

Consequently, traceability during outbreak and recall investigations requires the FDA to contact each link in the supply chain to work its way back to the source of fresh produce commodities like romaine lettuce.

Harris said, “more descriptive” labeling would greatly help in traceback situations. Even basic requirements for uniformity of records would help. Some businesses have handwritten records and others have electronic files. Either way, the records are often incomplete. 

Many in the fresh produce industry have not implemented the labeling designed by their own industry’s Produce Traceability Initiative. A common reason is that the labels would cost more.

Questions that remain unanswered as of this afternoon’s news conference, many because of the traceability problems, include:

Q. Is the outbreak over?
A. More cases are expected to be identified because of the lag time of two to three weeks between when a person becomes sick and the time it takes for lab tests, confirmation tests, reporting to local and state officials, and finally reporting to the CDC. There may also be new infections developing from unknown and possible ongoing distribution of Yuma-area romaine.

Q. Can you guarantee that the Yuma harvest is finished and no romaine is being shipped from that area?
A. No. Industry tells us the Yuma season is over and harvest has moved to California, but we haven’t been able to confirm that yet.

Q. Are any of the two dozen other growers’ fields adjacent to the Harrison Farm romaine field?
A. We don’t have those records yet.

Q. Is there a common irrigation water source for any of the fields?
A. We don’t have those records yet.

Q. What is the specific location of the Harrison Farm field that is implicated?
A. We don’t have that information yet.

Q. Is Harrison Farm growing or shipping any other fresh produce or more romaine?
A. The FDA does not have any information at this point to suggest that any other produce in involved. Harrison Farm is currently growing grass in its romaine field.

Q. Are there any common processors or shippers among the other farms you are investigating?
A. We haven’t received all of those records yet. We are looking at all points in the supply chain, from growers to the restaurants and retailers, as is the practice for all outbreak investigations.