What is E. Coli O157?

Ecoli warning

E. Coli O157 – What Is It & Why Do You Need To Be Aware Of It?


Escherichia coli, or E. coli for short, is a type of bacteria that lives in the intestines and is a normal part of the intestinal flora of humans and of animals. There are various strains of E. coli, most of which are innocuous (such as E.coli K-12) some types, however, can make you very ill indeed.

The main strain of E. Coli associated with human disease in the UK is E. coli O157. Symptoms of which commonly include severe abdominal and pain bloody diarrhoea. However, in more serious cases, E. coli O157 can cause kidney failure and even death! E. coli O157 produces a toxin (poison) called ‘Shiga toxin’.  There are also other types of Shiga-toxin-producing E. coli (STEC) to be aware of, some of which can make you just as ill as E. coli O157.

One of the most severe complications associated with E. coli poisoning is something called: ‘Hemolytic Uremic Syndrome’ (HUS). This is an infection that produces toxic substances which literally destroy red blood cells, which in turn, cause damage to the kidneys. HUS will typically require intensive care, kidney dialysis, and sometimes transfusions.

Although E. Coli O157 can multiply in food, it has a very low infective dose involving less than 100 bacteria. This is why food handlers must be so very careful and fully aware of the dangers! The main food vehicles associated with E-coli O157 are undercooked meat products, especially burgers and minced beef products. Other foods implicated include raw (unpasteurised) milk and soft cheeses made with unpasteurised milk. It is worth noting that E. Coli O157 can grow at a pH of 4.4, hence the reason why apple juice has also been implicated. E.coli O157 is relatively tolerant of acidic conditions and can also survive freezing, although numbers do start to decline at circa 4°C.

1996 saw the worst outbreak of E.coli 0157 ever recorded in Scotland; the outbreak, which was traced back to a butcher’s shop in Wishaw, resulted in 21 deaths, most victims being over 69 years of age.

E.coli, like most pathogens, can simply be destroyed by normal effective cooking. As a food handler you make sure that you:

  • Wash your hands always and often throughout the day
  • Ensure that you handle high-risk, ready-to-eat foods as little and as carefully as possible
  • Always segregate and keep completely separate raw and cooked foods
  • Have separate preparation areas for raw and cooked food
  • Clean and disinfect ‘as you go’.
  • Cook food properly (>75°C)