BERLIN (AP) — In their second major retraction in a week, German officials said initial tests provided no evidence that sprouts from an organic farm in northern Germany were the cause of the deadly E. coli outbreak. One U.S. expert called the German investigation "a disaster."
The surprise U-turn came only a day after the same state agency, Lower Saxony's agriculture ministry, held a news conference to announce that sprouts from the organic Gaertnerhof farm in the northern village of Bienenbuettel were suspected to be the cause of the outbreak. The ministry shut down the farm, recalled all its produce and sent an alert urging Germans not to eat any more sprouts.
Last week, German officials pointed to contaminated cucumbers from Spain as a possible cause, igniting vegetable bans and heated protests from Spanish farmers. Researchers later concluded the Spanish cucumbers were contaminated with a different strain of E. coli.
"This investigation has been a disaster," Michael Osterholm, director of the Center for Infectious Disease Research and Policy at the University of Minnesota, told The Associated Press.
"This kind of wishy-washy response is incompetent," he said, slamming German authorities for casting suspicion on cucumbers and sprouts without firm data.
But the European Union's Health Commissioner defended German investigators, saying they were under extreme pressure as the crisis kept unfolding.
"We have to understand that people in certain situations do have a responsibility to inform their citizens as soon as possible of any danger that could exist to them," John Dalli said in Brussels.
German Agriculture Minister Ilse Aigner on Monday reiterated the warning against eating sprouts, as well as tomatoes, cucumbers and lettuce.
But the German flip-flop on the sprouts means there is still no confirmed source for the deadliest known E. coli outbreak, which has already killed least 22 people and sickened more than 2,330 across Europe.
Over 630 of those victims are hospitalized with a rare, serious complication that can lead to kidney failure, and even E. coli victims without that condition have found themselves hospitalized for days with diarrhea and bloody stools. Hospitals in northern Germany have been overwhelmed by the crisis, with doctors and nurses working double shifts for weeks.
On Monday, the agriculture ministry for Lower-Saxony state said 23 of 40 samples from the organic sprouts farm tested negative for the highly aggressive, "super-toxic" strain of E. coli bacteria. It said tests were still under way on 17 other sprout samples from the farm.
"The search for the outbreak's cause is very difficult, as several weeks have passed since its suspected start," the ministry said in a statement, cautioning that further testing of the sprouts and their seeds was necessary.
However, negative test results on sprout or seed batches do not mean that previous sprout batches weren't contaminated.
"Contaminated food could have been completely processed and sold by now," admitted ministry spokeswoman Natascha Manski.
Osterholm, whose team has investigated a number of foodborne outbreaks in the U.S., said finding negative results in about half of the sprout tests was "meaningless" because it was possible that only a few sprouts in the entire batch were contaminated.
He said the contamination could be at such a low level that tests wouldn't pick it up and that to narrow down the source, more detailed studies of patients — what they ate and where — were necessary.
He also recommended that authorities should then trace back those food sources to their suppliers — which is exactly what led German officials to single out the sprout producer as a possible source, linking it to several restaurants where more than 50 people fell ill.
Since 1996, about 30 outbreaks of foodborne illness in the U.S. have been linked to raw or lightly cooked sprouts. Sprouts were also implicated a 1996 E. coli outbreak in Japan that killed 12 people and reportedly sickened more than 9,000.
The Lower Saxony ministry statement left consumers across the continent still puzzled as to what is safe to eat and warned that it was not clear how soon an answer would be found.
"A conclusion of the investigations and a clarification of the contamination's origin is not expected in the short term," the ministry said.
Andreas Hensel, the head of Germany's Federal Institute for Risk Assessment, added that it might never be possible to establish the outbreak's cause.
"We have to be clear on this: Maybe we won't be able anymore to identify the source," he told reporters in Berlin.
At an European Union health ministers meeting Monday in Luxembourg, Germany defended itself against claims it had acted prematurely in pointing toward Spanish cucumbers.
"The virus is so aggressive that we had to check every track," said Health State Secretary Annette Widmann-Mauz.
The EU will hold an emergency meeting of farm ministers Tuesday to address the crisis and its economic impact, including a ban by Russia on all EU vegetables.
At the organic farm in Bienenbuettel, between the northern cities of Hamburg and Hannover, there was no immediate reaction Monday by the owners. The gates remained locked. Two security guards patrolled while scores of television satellite trucks and journalists waited outside and a TV helicopter circled overhead.
Kirsten Grieshaber in Berlin, David Rising in Bienenbuettel, Raf Casert in Brussels and Daniel Wools in Madrid and AP Medical Writer Maria Cheng in London contributed to this report.