Following the recent E.coli O157 outbreak which has affected more than 100 people in the UK, which could be linked to eating contaminated mixed salad leaves, we thought it would be useful to take another look at this bacteria to identify the main characteristics and give an overview to controlling the bacteria in food premises and at home.

While most strains of E.coli are harmless and indeed are a natural part of our intestinal bacteria flora, some strains are pathogenic and can cause serious illness and even death (for example O157, O114 and more recently O26).

The first documented outbreak of E.coli 0157 in 1982 was in a fast food restaurant in the USA.  In 1996 21 people died and over 300 people were affected by food poisoning from E. coli O157 from one butchers shop in Scotland.     E. coli O104 caused a serious outbreak of foodborne illness in northern Germany between May and June 2011, in total 3,950 people were affected and 53 people died.  In June 2016, The Irish News reported, by Brendan Hughes, that a nursery in County Down had been closed due to an E-coli outbreak.  The E-coli 026 infection has been identified in eight children who attend the nursery.


Key facts about E-coli

  • Many strains of E-coli only require a small number of bacteria to infect people, in some cases it would seem that less than 100 organisms are required, so they don’t need to multiply to high levels to cause illness.
  • People can become infected in many ways including eating contaminated food or water, from equipment, hands etc being contaminated (E.coli is commonly found in faecal matter and if people don’t wash their hands this can be a real issue) and also direct contact with animals.
  • Undercooked mince and burgers, raw milk, unpasteurised cheese, apple juice, sprouting beans and salad leaves appear to have been the  main culprits of E-coli infection in recent years, but it’s worth noting that as the bacteria doesn’t need to multiply to high levels, any contaminated food could become the offending food vehicle.
  • The bacteria is not particularly heat resistant and does not produce spores, it will not multiply at low temperatures (although it is likely to survive in the refrigerator) and a report by the US National Center for Biotechnology indicates that it can be destroyed by common disinfectants.


Control measures.

Ways in which we can control E-coli breakouts includes:

  • Sourcing a reputable supplier
  • Ensuring a safe , wholesome water supply
  • Chlorination (for  food production and safe sewage disposal).
  • Ensuring raw foods and ready to eat foods are kept separate throughout the food journey,  from purchase to service
  • Thorough cooking of meats especially of poultry and pork
  • Pasturisation, particularly of milk, cheeses and meats used in pates.
  • Provision of dedicated equipment for different foods
  • Effective cleaning and disinfection procedures
  • Using foods within their date codes
  • Effective hand washing
  • Food handlers reporting illness and exclusion of ill staff from food handling duties
  • Effective use of Personal Protective Equipment (PPE) when working with different food types.