Two people have died and 160 cases have been confirmed. This included 153 cases in England, six in Wales and one in Scotland.
PHE said that the latest figures suggested that the outbreak was now subsiding.
However, it said that the outbreak control team “remain vigilant” to further cases and to the risk of those affected passing the infection to others.
PHE has said that a number of people affected had eaten salad leaves, including rocket, prior to becoming ill.
The source of the outbreak was still unconfirmed and investigations by the Food Standards Agency are continuing.
PHE testing has revealed that the strain was likely to be imported, possibly from countries bordering the Mediterranean sea.
‘Over the worst of this outbreak’
Dr Isabel Oliver, director of PHE’s field epidemiology service, said: “We are pleased to see a very significant reduction in the number of cases with nine reported over the past week.
“This could indicate that we are over the worst of this outbreak, with those affected reporting the last onset of symptoms on July 5.
“But this is still too many, and the risk of those affected passing the infection onto others remains.”
Strict hygiene measures were an essential precaution for anyone affected, to stop the infection passing to others, added Oliver.
The PHE boss advised anyone handling food to remove any loose soil before storing vegetables and thoroughly wash all vegetables (including salads) that would be eaten raw unless they had been pre-prepared and were specifically labelled ‘ready to eat’.
Not ruling out other food items
Oliver added: “The source of the outbreak remains unconfirmed and under investigation; we are not ruling out other food items.
“It’s important to be aware that no individual wholesaler, supplier, retailer, or restaurant has been confirmed as the source and currently the Food Standard Agency’s investigations focus on the distribution of mixed salad leaves to wholesale and not supermarkets.”
A small number of wholesalers continue to be advised to cease adding some non-UK salad leaves to their mixed salad products pending further investigations.
People were still being advised to wash hands thoroughly using soap and water after using the toilet, before and after handling food and after contact with any animals and pets, including farm animals.
Read more about the fatal outbreak here.
Fatal E.coli outbreak timeline
- July 5: PHE said it was continuing to investigate the outbreak which had affected 109 people. It identified salad leaves as the likely cause
- July 14: Investigations continue but two people died and 151 cases were confirmed
- July 20: FSA confirmed the investigation would look at the food supply chain, including food manufacturers
- July 21: Outbreak seemed to be subsiding with 160 cases now identified