The farm at the epicenter of the German sprout storm that has killed 53 and sickened over 4,000 from E. coli O104 is sparkling clean to reopen after testing and removal of all fenugreek seeds.

But as science-types have pointed out, the farm may function with the clarity and cleanliness of Marie Antoinette’s but that won’t prevent future outbreaks if the seeds themselves are contaminated.

As reported by the European Food Safety Authority (EFSA), despite the epidemic curve’s trending down, the outbreak can’t be considered over. The ultimate source — the contaminated seeds from which salad sprouts were grown — has been so widely distributed that no one really knows where they have gone or for how long they might remain for sale. One prediction, based on the probable package labeling, is that they could remain on shelves for 3 more years.

Wired magazine reported the first wave of cases, in Germany in May, arose from a firm that grew and sold sprouts at wholesale. The sprouts from that farm would subsequently be linked to 41 separate clusters of cases; all of them could be traced back to that facility’s sprouts, re-sold as a produce item somewhere in Europe.

A second wave, in France in June, initially confounded investigators. Out of those 16 cases, 11 had attended the same event. They did eat sprouts there — but not sprouts from the German farm. Instead, the sprouts had been grown by the event’s catering firm, from seeds the company had bought at an everyday garden center.

That shifted the focus from the German farm’s practices to the seeds that both the farm and the caterer used. The German farm sold two blends of grown sprouts, spicy (grown from fenugreek and radish seeds and black and brown lentils) and mild (fenugreek and alfalfa seeds, adzuki beans and lentils). The French caterer had used three seed types: fenugreek, mustard and rocket (or roquette; what Americans call arugula). The only type in common with both companies and all the mixtures was fenugreek.

That discovery sent EU investigators in pursuit of fenugreek seeds back down the European food chain, in a rapid-fire search that deployed personnel from eight countries’ food agencies as well as the ECDC, World Health Organization and the Food and Agriculture Organization of the United Nations. They drafted a detailed 4-page questionnaire that fed data into Excel spreadsheets and a relational database. They crunched (and crunched and crunched) the numbers, and this is what emerged:

All of the seeds came from a single shipment that left a port in Egypt almost 2 years earlier, on Nov. 24, 2009.

The seeds took a tortuous path. That initial shipment — which was immense, 15,000 kg (33,000 lbs) — was containerized at the port of Damietta in Egypt, shipped by boat to Antwerp in Belgium, went by barge to Rotterdam in the Netherlands where it passed customs, and then was trucked to Germany. There, an importer broke up the shipment:
10,500 kg to a single German distributor;
3,550 kg to nine other German companies;
375 kg to a Spanish company;
250 kg to an Austrian distributor that sold the entire lot to a single Austrian company;
and 400 kg to a company in England.

The German importer broke up the 10,500-kg shipment into multiple lots. Only 75 kg ended up at the German farm that sparked the first wave of illness. The rest went to 16 other companies. One of those 16 broke its shipment up further, selling the seeds on to 70 additional companies: 54 in Germany, 16 in 11 other countries within the EU.

A new report details the complexities of the E. coli O104 outbreak investigation. Thanks to Albert Amgar in France for sending it along.

Source food from safe sources; including seeds and other inputs.