A senior German doctor has said that the puzzling outbreak of E. coli poisoning that has now spread to 12 countries appears to be stabilising even as the death toll rose to 19.
As authorities continued to hunt the elusive source of the killer bug, the latest death was of an 80-year-old woman in the northern German state of Mecklenburg-Western Pomerania on Friday.
But while German authorities were still warning consumers off raw vegetables, the EU's Reference Laboratory for E. coli in Rome said scientific tests had failed to support a link to the outbreak.
German Chancellor Angela Merkel defended an earlier false alarm on organic Spanish cucumbers that angered Madrid, as Prime Minister Vladimir Putin said he would not allow Russians to "get poisoned" by EU vegetables.
"The situation is that the number of new infections appears to be stabilising somewhat," Reinhard Brunkhorst, president of the German Nephrology Society, told reporters in Hamburg, the epicentre of the scare.
But he added: "We are dealing here in fact with the biggest epidemic caused by bacteria in recent decades."
All but one of the fatalities since the outbreak of enterohaemorrhagic E. coli (EHEC) poisoning began last month have occurred in Germany. A patient who died in Sweden had recently returned from Germany.
Regional German health authorities have reported more than 2,000 cases of people falling ill with EHEC poisoning, with symptoms including stomach cramps, diarrhoea, fever and vomiting.
A large majority are female, suggesting that the source is "probably something that women prefer more than men," Andrea Ellis, an epidemiologist at the World Health Organisation's (WHO) department of food safety, said in Geneva.
In some cases the infection can lead to bloody diarrhoea and potentially life-threatening conditions such as haemolytic uraemic syndrome (HUS), a kidney disease.
At least 552 people, 520 of them in Germany, have HUS, according to the WHO, with 10 other European countries plus the United States reporting HUS or EHEC infections.
The outbreak was "the largest epidemic of HUS to have occurred anywhere in the world," according to Francois-Xavier Weill, head of France's National Reference Centre for E. coli.
All cases except two involve people who live in or had recently visited northern Germany, or, in one case, had contact with a visitor from there.
Britain confirmed four more cases of poisoning on Friday, bringing the total number of infected in the country to 11.
Each is related to German travel and three of the patients have HUS, the Health Protection Agency said.
Merkel defended last week's false cucumber alert in a phone call Thursday with Prime Minister Jose Luis Rodriguez Zapatero, saying authorities were "duty-bound to inform the public at all times."
The advisory, retracted this week, left tens of thousands of tonnes of Spanish produce unsold, costing Spanish growers an estimated 200 million euros ($290 million) a week.
Both Berlin and Madrid said they had agreed to seek compensation at the European level.
Hungary, which currently holds the rotating EU presidency, said it aimed to hold an extraordinary meeting of the bloc's farm ministers to discuss the outbreak, most likely on June 17.
The Robert Koch Institute (RKI), Germany's national disease centre, still advises consumers, primarily in the north of the country, to avoid cucumbers, tomatoes and lettuce. But the EU laboratory said it remained sceptical.
"Alarmism over the consumption of vegetables is not justified... since laboratory analyses do not support the hypothesis that contaminated vegetables were the source of the infection," it said.
With no clarity on the source of the mysterious bacteria, the outbreak has led some countries such as Russia and Lebanon to ban vegetables from the EU, in moves criticised by the 27-member bloc.
Fernando Valenzuela, the head of an EU delegation to Russia, said the ban went "in the opposition direction" of Moscow's hopes to join the World Trade Organisation.
Putin said he would check the validity of Moscow's ban but expressed bewilderment at the idea that the move was against the spirit of WTO membership.
"People really are dying because of eating these products and we cannot let our people get poisoned for the sake of some kind of spirit," he added.