A single shipment of fenugreek seeds from Egypt is now thought to be the most likely source of the recent E coli outbreak in Europe.
The European Union has voted to ban imports of all seeds and beans from Egypt until 31 October.
More than 4,100 people in Europe and in North America have been infected in two outbreaks of E coli infection - one centred in northern Germany and one focused around the French city of Bordeaux.
Almost all of those affected in the first outbreak - the deadliest on record - lived in Germany or had recently travelled there.
The infection has killed 48 people in Germany and one person in Sweden so far.
The European Food Safety Authority has urged the European Commission to make 'all efforts' to prevent any further consumer exposure to suspect seeds.
It advised consumers not to eat sprouts or sprouted seeds unless they are thoroughly cooked.
'The analysis of information from the French and German outbreaks leads to the conclusion that an imported lot of fenugreek seeds which was used to grow sprouts imported from Egypt by a German importer is the most common likely link,' the EFSA said in a statement.
But it added that 'other lots of fenugreek imported from Egypt during the period 2009 to 2011 may be implicated'.
Investigations should be carried out in all countries that may have received seeds from the lots concerned, the EFSA said.
The strain of E coli infections identified in the outbreaks, known as STEC O104:H4, can cause serious diarrhoea and in severe cases kidney failure and death.