The Centers for Disease Control and Prevention (CDC) and the US Food and Drug Administration (FDA) engaged in a collaborative investigation of an E. coli O157 outbreak ultimately linked to alfalfa sprouts produced by Jack & The Green Sprouts, a River Falls, Wisconsin company. Both federal agencies issued separate announcements on March 25th declaring that this outbreak of E. coli is over.
Recollections of a Recall: Jack & the Green Sprouts
The first news of a potential outbreak came in the form of an August 24th press release from Minnesota Department of Health. The release announced that routine disease monitoring by the state department identified seven cases of E. coli O157:NM with onset dates in January an early February. When the state laboratory sequenced the bacteria, all seven cases involved a strain of E. coli O157:NM with the same DNA fingerprint.
The initial group of ill Minnesotans ranged in age from 18 to 84 years and comprised of two men and five women. All seven were permanent residents of Minnesota – four cases resided in the Twin Cities metro area at the time of the outbreak, and the other three lived in the greater Minnesota area. Two of the Minnesota outbreak cases had been hospitalized, but both had recovered by the time of the initial outbreak announcement by state and federal agencies.
The initial Minnesota press release added two confirmed outbreak cases of E. coli O157 in two Wisconsin residents to the initial outbreak count, which stood at nine. The Wisconsin Department of Health Services (WDHS) identified the two cases that involving residents of that state.
With exception of the two hospitalized cases discussed above, both of which had recovered by the time the outbreak was announced, no cases associated with the Jack & the Green Sprout E. coli outbreak required hospitalization.
Investigation of the outbreak was undertaken by Minnesota officials working in cooperation with investigators from the Centers for Disease Control and Prevention (CDC), the U.S. Food and Drug Administration (FDA), WDHS, and the Wisconsin Department of Agriculture, Trade and Consumer Protection (WIDATCP)
\\E. coli O157 casesannounced that contaminated alfalfa sprouts have caused 9 cases of E. coli O157:NM. All nine cases are in Wisconsin and Minnesota.
This is the second outbreak linked to alfalfa sprouts announced in six days, as the Kansas Department of Health and Environment made the initial announcement of a multistate Salmonella outbreak linked to alfalfa sprouts produced at Kansas’ Sweetwater Farms.
The ongoing outbreak of E. coli O157:NM has been tied to alfalfa sprouts produced by Jack & the Green Sprouts, a distributor located in River Falls, Wisconsin. The company distributes alfalfa sprouts throughout the upper Midwest. The MDH says that distribution may extend to states outside of the upper Midwest as well.
Routine disease monitoring conducted by the MDH found seven cases of E. coli O157:NM with dates of onset in January or early February that involved bacteria with the same DNA fingerprint. Of the Minnesota cases, four of the infected individuals are male. The youngest Minnesota outbreak victim is 18; the oldest is 84. Two of the cases required hospitalization due to the severity of the illness.
Two additional cases of E. coli O157:NM were identified in Wisconsin residents by the Wisconsin Department of Health Services (WDHS), bringing the total number of outbreak cases to nine. Fortunately, the cases in Wisconsin were not severe enough to require hospitalization.
Identification of the source of the outbreak, usually the most challenging element of the investigations carried out by public health officials in connection with outbreaks due to foodborne pathogens, had been completed at the time the first public announcements related to the outbreak were made.
State, local, and federal public health and regulatory officials had collaborated in a joint effort to isolate the outbreak source. A key component of the investigation involved interviewing confirmed cases about foods consumed and places visited in the week or so prior to becoming ill. Of the eight outbreak cases interviewed, all 8 (100%) indicated that they had definitely or likely consumed alfalfa sprouts in the week prior to falling ill.
Investigators completed traceback investigations from seven different places where people with confirmed cases had consumed or purchased sprouts. All seven tracebacks – each a mini-investigation of its own – led health officials to Jack & the Green Sprouts once again.
Announcement of Ongoing Outbreak Followed Shortly by Product Recall
The Minnesota Department of Health issued its announcement regarding the ongoing two-state outbreak on February 24th. On February 25th, the CDC and FDA both issued their own announcements of the ongoing recall and agency investigative efforts to-date.
The company that produced the contaminated sprouts made perhaps the most important announcement of the day when it issued a voluntary recall for all alfalfa sprouts and alfalfa onion sprouts produced and distributed by the company.
Investigators turned towards investigating the the extent of the product contamination. The efforts involved state officials working with the FDA to collect samples from the Jack & the Green Sprouts facility to further narrow down the outbreak source, and hopefully enable officials to identify how the sprouts came to be infected with E. coli in the first place.|
The MDH announcement followed the CDC announcement of another alfalfa sprout-related outbreak of Salmonella Muenchen earlier in the week. Subsequent investigative efforts demonstrated, however, that the two outbreaks involving contaminated alfalfa sprouts were not in any way connected.
Post-Outbreak Investigations Yield Little Additional Insight
Investigators were not able to determine the manner in which the E. coli bacteria came to infect the company’s sprouts. This isn’t particularly surprising, however, given sprouts’ status as one of the most commonplace and well-known sources of foodborne illness.
Following the initial outbreak announcement, officials reported one more case involving the outbreak strain of E. coli O157:NM in each state. The two additional cases brought the outbreak total to 11, where it remained when officials announced the official end of the outbreak on March 25th.
Sprouts are commonly isolated as the source of E. coli, Salmonella and listeria outbreaks, and health officials recommend that the elderly, children, pregnant women and immunocompromised individuals avoid eating raw sprouts of any kind (examples include alfalfa spouts, mung bean sprouts, clover, and radish).