The Strange SunSprout Salmonella Outbreak

March 18, 2009

On March 3rd, SunSprout Enterprises (Omaha, NE) recalled several production codes of Alfalfa, Onion, and Gourmet Sprouts after the company's sprouts were presumptively linked to a four-state outbreak of Salmonella Saintpaul infections.

The recalled sprouts had been shipped to distributors in Iowa and Nebraska for resale to restaurants and retailers.

Since the March 3rd recall announcement, the number of suspect and confirmed outbreak cases has grown to as many as 140, including:

• Iowa (as of March 3): 5 confirmed; 4 suspect
  
• Kansas (as of March 6): 5 confirmed
  
• Nebraska (as of March 17): 84 confirmed; 13 suspect
  
• South Dakota (as of March 12): 5 confirmed; 24 suspect
  

With this many cases in a regional outbreak, one has to wonder why investigators have been unable so far to find the outbreak strain either in a sample of the implicated sprouts or in the production facility. Is there another possible explanation?

We know that the outbreak strain has been identified as Salmonella Saintpaul, the same Salmonella serogroup that was responsible for last year's jalapeño/serrano pepper outbreak. We haven't yet learned whether there is any similarity between the genetic fingerprints of the 2008 Salmonella Saintpaul and this year's outbreak strain.

We also know that raw sprouts often are used to garnish fresh salads. Could the source of the problem be a different salad item? Tomatoes? Lettuce? Cucumbers?

After last year's Salmonella Saintpaul outbreak, FDA did NOT add imported peppers from Mexico to its Automatic Detention Import Alert list. Instead, the agency chose to monitor imports and reject specific shipments if lab results warranted.

As we learned last year, this import surveillance program catches only a small percentage of contaminated foods. Even so, in January and February of this year, FDA reported several refusals of various produce items from Mexico after Salmonella was detected in the shipments – including a shipment of serrano peppers, and several shipments of fresh cucumbers.

It can be difficult – again, as we saw last year – to parse epidemiological reports and tease out a probable contamination source when several different foods usually are consumed together. The initial suspicion that has fallen on sprouts from SunSprout Enterprises may prove to be correct. 

But we won't be surprised if the spotlight shifts to another possible outbreak source.