The government warned of more deaths to come, despite the source having been identified and new infections falling even as the toll rose to 35.
"More fatalities cannot be ruled out, painful though it is to say so," Health Minister Daniel Bahr told the Bild am Sonntag newspaper, two days after the source was identified as vegetable sprouts grown in northern Germany.
"The continuing fall in the number of new infections gives grounds for optimism. But that does not rule out more cases of EHEC (enterohaemorrhagic E. coli)," he said.
The Robert Koch Institute (RKI), Germany's national disease agency, said Sunday meanwhile that the death toll had risen to 35, but that the rate of new infections had continued to abate.
"The outbreak is receding," RKI spokesman Guenther Dettweiler told AFP.
All but one of the 35 deaths from EHEC poisoning have been in Germany, with the other being a woman in Sweden who had recently travelled to Germany.
Some 3,255 people have also fallen sick in 14 European countries plus the United States and Canada, according to the World Health Organisation. All but five cases were in people who lived or had visited Germany.
Many are seriously ill with bloody diarrhoea and potentially life-threatening conditions such as haemolytic uraemic syndrome (HUS), a serious kidney ailment.
The WHO said Saturday that 812 people had HUS, 773 of them in Germany.
In Germany, some 100 patients have such bad kidney damage that they need an organ transplant "or will require dialysis treatment for the rest of their lives", said Karl Lauterbach, health expert for the Social Democrats party.
After several frantic weeks of searching, German authorities on Friday said they had identified the source as being vegetable sprouts from an organic farm in Lower Saxony, northern Germany.
The farm has been closed and all its products recalled. The farm cultivated sprouts from a variety of products including lettuce, azuki beans, mung beans, fenugreek, alfalfa and lentils.
Authorities have said though that the farm in the northern village of Bienenbuettel had done nothing wrong, with Gert Lindemann, Lower Saxony agriculture minister, saying it had "high hygiene standards".
With German authorities only late last week dropping advice, particularly in northern Germany, to avoid uncooked tomatoes, cucumbers and lettuce, the scare has cost European farmers hundreds of millions of euros (dollars).
The RKI still recommends not eating raw vegetable sprouts.
Particularly badly hit were Spanish producers after Germany initially and erroneously blamed cucumbers grown there.
The European Commission has offered 210 million euros ($303 million) to farmers affected across Europe.
Russia also banned the import of all fresh vegetables from the whole of the 27-nation European Union. Moscow agreed at a summit with the EU on Friday to lift the ban.