By: Heather Williams

Could we be experiencing a Multi-Country Outbreak? Canada has found themselves in the midst of an E. coli O157:H7 outbreak. They have linked it to romaine lettuce. This week, the United States’ Centers for Disease Control and Prevention released a public notice that we too are in the midst of an outbreak. The two agencies imply that romaine lettuce may be the source of the United States outbreak too.

Shiga toxin-producing E. coli O157:H7 has infected seventeen people across thirteen states including: California, Connecticut, Illinois, Indiana, Michigan, Nebraska, New Hampshire, New York, Ohio, Pennsylvania, Virginia, Vermont, and Washington.  Illness onset for the United States cases range from November 15, 2017 to December 8, 2017.  Currently the Public Health Agency of Canada is investigating an outbreak of STEC O157:H7 of their own that has spanned several provinces.  While preliminary, the CDC and Canadian agency implies that it seems that the type of E. coli we are seeing here in the United States is genetically closely related to the type of E. coli making Canadians ill.  This is an indicator that there is a likelihood of sharing a common source of infection.

Canadian Outbreak

The Public Health Agency of Canada has been issuing Public Health Notices as early as November 11, 2017 indicating illness onset during an undisclosed date range in November.  On the first Public Health Notice, the agency indicated that 21 cases of E. coli illness had been linked across 3 provinces including Quebec, New Brunswick, and Newfoundland and Labrador.

Additional updates trickled in as more and more have become affected.  December 14, 2017, two additional provinces including Ontario and Nova Scotia were added along with 9 additional illnesses.  At this time a death was reported related to the outbreak.  December 21, 2017 an additional 10 cases were linked to the outbreak.  At this time romaine lettuce was indicated as a possible source for the outbreak.  In fact, the Public Health Agency of Canada advised individuals residing in the affected provinces of Ontario, Quebec, New Brunswick, Nova Scotia, and Newfoundland and Labrador to avoid romaine lettuce and consider consuming other types of lettuce instead until more is known about the source of the outbreak.

The latest Canadian update on December 28, 2017 comes on the same day as the first Center for Disease Control and Prevention (CDC) update for the United States.  One additional case was reported in the Canadian outbreak bringing the total to 41 cases, 16 cases requiring hospitalization, and 1 death.  The Public Health Agency of Canada indicated the ongoing risk of E. coli infections seems to be associated with consumption of romaine lettuce in Eastern Canadian provinces.

No Recall So Far

At this time no recall as been initiated by the Food and Drug Administration or the Canadian health agencies.  The romaine lettuce that could be responsible for the Canadian outbreak has not been tracked to a specific vendor.  Romaine has been implicated because it is a common carrier for E. coli, and Canadian outbreak victims have indicated eating romaine lettuce from various sources prior to becoming ill.  Prepared salads bought from grocery stores, salads and lettuce at restaurants and fast food chains were also reported by outbreak victims as potential sources of contaminated romaine lettuce consumption.  Canadian public health investigators are working with the Canadian Food Inspection Agency to narrow down a source for the contaminated romaine lettuce, but it is a long and difficult process.

Based on growing season and existing supply chain patterns, either the United States or Mexico are high on the list of likely sources.  Though it remains unknown if those who have been interviewed have indicated a link between whole heads of romaine or chopped, or whether bagged romaine was more likely than picked produce.  Canadian officials have not released any specific details and as a result, no products have been recalled at this time.

The concerning part of the unknown is that contaminated product may still be in circulation and already in consumers’ homes, restaurants ready to serve unknowing patrons, or even at grocery stores and food service operations.  Distribution centers and other points in the food supply chain across the country and spanning countries could be carrying this tainted product to additional victims.  With a shelf life of up to five weeks, the product can hang around for quite some time.  Canadian health officials have urged people to discard all romaine lettuce.  “These illnesses indicate that contaminated romaine lettuce may still be on the market – including in restaurants, grocery stores, and any establishments that serve food,” reported the Public Health Agency of Canada.

Ongoing Risk for Canadians (And Those from the US) if Source Not Identified

If people stop consuming the product temporarily, eventually the illness will stop, and the risk of E. coli illness will be gone, right?  Unfortunately, that is just not the case.  The threat risk does not end there.  Even if the last crop of the season was harvested from the implicated romaine lettuce grower, the risk of E. coli contamination can continue.

If Source is Growing Field

If the source ends up being the growing field, E. coli can remain in the soil and contaminate the next crop rotated into that spot.  This could start another outbreak with the same product next season or even another product entirely depending on how the farmer manages the crops.  Sometimes a different crop is immediately placed in that field with different soil requirements or fertilization is added to make the soil usable more quickly.  Either way, it is unlikely that the field will never be used again, so if no mitigating activities take place to handle the E. coli present, we will certainly see another E. coli outbreak in the near future.

If the Source is a Packaging/Processing Facility

If the source turns out to be linked to a packaging or processing facility, we are likely to see another outbreak very soon linked to another product.  These facilities can manage many different product types and distribute the product across the country and even to other countries.  If the facility is identified as the source, additional outbreaks are sure to emerge until the facility is properly decontaminated.

United States and Mexico as Potential Sources

While our Canadian neighbors experienced the issue first, based on growing seasons it seems that the source of Romaine (while not yet confirmed) could have originated from farms in either the United States or Mexico.  Different climates lend to specific crops and specific times of the year.  For this reason, to maintain a variety of produce in different regions and/or countries, importing produce is a common activity.

While it makes sense that the United States and Canada may have received produce from the same farm or facility, it is interesting to note that the Canadians experienced illness reported sooner than Americans.  This is just one more piece to the puzzle that investigators will have to link to identify where the contaminated product originated.

For now, though no specific guidance has been issued, it would be a good idea to avoid romaine lettuce or thoroughly wash any produce prior to consumption.

UnsafeFoods will continue to monitor the situation and provide updates as they become available.

 

Sources:

https://www.canada.ca/en/public-health/services/public-health-notices/2017/public-health-notice-outbreak-e-coli-infections-linked-romaine-lettuce.html

https://www.cdc.gov/media/releases/2017/s1228-e-coli-outbreak.html