A-ha! It was the sprouts after all.
Even though tests from an organic farm in Northern Germany failed to detect the Escherichia coli strain that has sickened more than 3,000 and killed 31, German disease gumshoes concluded from the pattern of cases that sprouts are to blame.
"It is the sprouts," Reinhard Burger, head of Germany's Robert Koch Institute, said Friday at a media briefing. How does he know? The institute, along with two other government groups, linked clusters of illness to 26 restaurants and cafeterias that got sprouts from the same grower in the German state of Lower Saxony, the Associated Press reports.
German officials lifted warnings against the consumption of cucumbers, lettuce and tomatoes as a result of the finding. It's possible that by now all the tainted sprouts have been eaten or discarded. The farm that was suspected as the E. coli source was shut down more than a week ago. Even so, the government continued to warn people not to eat sprouts.
As the outbreak widened, German health authorities were criticized for issuing contradictory information — such as an early warning against Spanish cucumbers that officials in that country disputed — and for being too slow to reach a conclusion about the cause.
On Wednesday's All Things Considered, Dr. David Acheson, formerly of the Food and Drug Administration, suggested German investigators were too hung up on finding a smoking gun — a food sample testing positive for the particular strain of germ isolated from sick people.
"This far out in the outbreak that could be almost impossible to find," Acheson told host Michele Norris, "because the food has either been consumed or spoiled and has been thrown away."
In many U.S. investigations, he explained, authorities relied on "solid epidemiology without actually having a positive sample, like spinach in 2006 which was obviously a massive E. coli outbreak. And it was very evident from the epidemiology that it was spinach."
The problem with looking for a positive test from samples is that "the further you are away from the start of the outbreak the harder it's going to be to do that, and so you continue to struggle," he said.