Enterohaemorrhagic E. coli (EHEC), which has sparked a food-health scare in Germany, has already killed 31 people and infected 3,000 since the first cases were reported on May 24.

Here is a timeline of how the food crisis developed:

- May 24: German authorities report three suspected deaths from a strain of the E. coli bacterium and warn more are likely because of a "scarily high" number of new infections.

They say more than 80 cases of haemolytic uraemic syndrome (HUS) have been reported in the past two weeks, a life-threatening disease caused by infection with the enterohaemorrhagic E. coli strain. The northern city of Hamburg is particularly affected.

- 25: Germany warns consumers to be especially careful when eating tomatoes, lettuce, and cucumbers which are believed to be responsible for the outbreak of food poisoning.

- 26: Health authorities of Hamburg identify three cucumbers from Spain as the cause of the disease, along with a fourth whose origin is unknown.

The European Commission urges people who recently visited Germany to watch for symptoms such as bloody diarrhoea.

Other countries which have seen cases of the food poisoning are Sweden, Denmark, Britain and the Netherlands.

- 27: Spain's agriculture minister, Rosa Aguilar, says there is "no proof" it is to blame.

- 30: Russia bans the import of all vegetables from Germany and Spain.

- 31: Germany voices doubt over whether Spanish cucumbers were responsible for the spread of the killer bacteria.

Spain and the Netherlands demand EU compensation after their vegetable sales collapse. Germany joins them in their demand.

- June 1: Europe's top health official John Dalli says the bloc is confronted with "a serious crisis" and that further testing is needed to pinpoint the source of the outbreak.

- 2: Russia bans imports of fresh vegetables from the 27 EU member states.

- 3: Scientific checks have failed to support the hypothesis that contaminated vegetables are behind the outbreak: EU's scientists.

- 5: Vegetable sprouts from the German state of Lower-Saxony are suspected of being the source of the outbreak: region's health ministry.

- 8: The number of new killer bacteria infections is dropping in Germany, Health Minister Daniel Bahr says.

The European Union Commission raises its offer of compensation to 210 million euros for vegetable farmers, from an earlier 150 million euros.

- 9: The death toll reaches 31, after a 75-year-old infected woman dies in the northern state of Lower Saxony.

- 10: Germany identifies contaminated sprouts as the source of the bacteria, lifts its warning on eating raw lettuce, tomatoes and cucumbers.

Russia agrees to lift its import ban on EU vegetables, EU Commission chief Jose Manuel Barroso says after talks with Russian leaders.

(c) 2011 AFP