Dr Stephen Morton, head of the multi-agency Outbreak Control Team, has said the public need take no action over the findings:
This outbreak was fortunately short lived but it was important to see if we could find the source. Our findings suggest that eating mixed leaf bagged salad was the most likely cause of illness.
It is however often difficult to identify the source of short lived outbreaks of this type as by the time that the outbreak can be investigated, the affected food and much of the microbiological evidence may no longer be available ...
There is no specific action for the public to take but we hope the investigations ... will help to prevent further outbreaks of this type from happening again.