Yesterday I gave a talk to fresh produce farmers and told them that outbreaks happen all the time and only in special cases, when all the right data is available, are health officials able to pinpoint a cause. I think it made some of the audience mad, but that’s the reality. Outbreak investigations are at the mercy of individual recall and product movement and condition attributes. All of which are often incomplete. It’s like my kids trying to put together a puzzle without the corner or border pieces. Health officials in Missouri announced yesterday that their investigation into an outbreak of pathogenic E. coli has ended. With no real answers. While preliminary epidemiology pointed to an association with eating food purchased from Schnuck’s salad bars, that was as far as things got.

According to Missouri Net, the data just wasn’t there.

Director Margaret Donnelly says the inspections and food trace-back investigation by federal agencies were extensive, but did not reveal a definitive source. She says a grower in California was suspected of being connected but records were “insufficient to complete the picture.” She told the House Appropriations Committee on Health, Mental Health and Social Services it is not unusual for a source to go unidentified. “The food which caused the outbreak is identified in less than 50 percent of food bourne (sic) outbreaks, and the reason for that is because of the amount of time that passes from when the person is exposed to the pathogen until the public health receives a report. This incubation period can be up to ten days. In addition, after that period of time, food products are often no longer available for analysis.”