German health officials are still looking for the cause of the outbreak that began on May 2. So far, the super-toxic strain of E.coli has killed 24 people, infected over 2,400 and left hundreds hospitalised with a serious complication that can lead to kidney failure. New cases are still being reported every day - 94 more in Germany yesterday.
"If we don't know the likely culprit in a week's time, we may never know the cause," Dr. Guenael Rodier, the director of communicable diseases at the World Health Organization, told The Associated Press in an interview Tuesday.
Experts say the outbreak could have been spotted sooner with better medical detection and immediate interviews with patients about what they ate.
German officials accused Spanish cucumbers of being the culprit last week but had to retract when the cucumbers had a different strain of E.coli. On Sunday, they blamed German sprouts, only to backtrack a day later when initial tests were negative.
Rodier said the contaminated vegetables have probably disappeared from the market and it would be difficult for German investigators to link patients to contaminated produce weeks after they first became infected.
Other experts were even more critical of the German investigation.
"If you gave us 200 cases and 5 days, we should be able to solve this outbreak," said Michael Osterholm, director of the Center for Infectious Disease Research and Policy at the University of Minnesota, whose team has contained numerous food-borne outbreaks in the United States.
Osterholm described the German effort as "erratic" and "a disaster" and said officials should have done more detailed patient interviews as soon as the epidemic began. He also disputed the idea it might be impossible to find the outbreak's source.
"To say we may never solve this is just an excuse for an ongoing bad investigation," he said. "This is like a cold murder case where you go back and re-examine the evidence."
Even German lawmakers have slammed the government's chaotic response to the outbreak, criticising the confusing announcements and retractions.
Christine Clauss, Saxony's state health minister and a member of Chancellor Angela Merkel's own governing party, said states were initially conducting their own investigations into the outbreak.
"It would be especially important to cooperate more closely and in a more centralised way in situations with a nationwide germ," she told the daily newspaper Leipziger Volkszeitung.
Karl Lauterbach, a doctor who serves as the health expert for the opposition Social Democrats, has repeatedly urged the government to set up a national crisis team to counter the lack of coordination and the leadership vacuum among the federal and state authorities responding to the crisis.
Paul Hunter, a professor of health protection at the University of East Anglia in England, said German investigators could have picked up the outbreak sooner if doctors regularly did lab tests on patients with diarrhea - a standard practice in Britain.
"They could miss an outbreak starting until people get quite sick with severe complications," he said.
Hunter said German doctors probably only realized how big the outbreak was when the number of patients with kidney failure spiked in mid-May.
Yesterday, the EU health chief warned Germany against issuing any more premature - and inaccurate - conclusions about the source of contaminated food. EU health chief John Dalli told the EU parliament in Strasbourg that information must be scientifically sound and foolproof before it becomes public.
"It is crucial that national authorities do not rush to give information on the source of infection that is not proven by bacteriological analysis, as this spreads unjustified fears (among) the population all over Europe and creates problems for our food producers," Dalli said.
Tests are continuing on sprouts from an organic farm in northern Germany, but have so far come back negative. Rodier said that doesn't necessarily exonerate the vegetables.
"Just because tests are negative doesn't mean you can rule them out," he said. "The bacteria could have been in just one batch of contaminated food and by the time you collect specimens from the samples that are left, it could be gone."
Hunter said the outbreak could have devastating consequences for consumers' faith in food safety.
"The impression among many people may be that the German officials haven't got a clue what they're doing, even if that's far from the case," he said. "They just have not done a good job of explaining why their assessments keep changing and as a result, it may be a long time before many people eat cucumbers and sprouts again."
In Luxembourg, major vegetable producers Spain, Italy and France angrily demanded compensation Tuesday for farmers blindsided by huge losses in the E.coli outbreak. In response, EU Farm Commissioner Dacian Ciolos promised more than euro150 million ($219 million) in aid.
European farmers say they are losing up to 417 million euros a week.
Germany's national disease control centre, the Robert Koch Institute, on Tuesday raised the number deaths to 24 - 23 in Germany and one in Sweden - and the number of infections in Germany to 2,325, including 642 patients with a rare complication that may lead to kidney failure. Ten other European countries and the United States have another 100 cases.
The institute said the number of new cases had declined - a sign the epidemic might have reached its peak - but added it was not certain whether that decrease will continue.
Hospitals in northern Germany were still being crushed by the demands of caring for so many E.coli patients.
A 41-year-old Hamburg lawyer was hospitalised for more than a week in a separate hospital ward for E.coli cases.
"When I got there, it wasn't that full yet, but then more patients came every day," she told the Sueddeutsche Zeitung newspaper, speaking on condition of anonymity because she didn't want to identify her family. Now cured, she remains quarantined at home with no physical contact to avoid infecting anyone.
"People here are very, very much afraid," she said.