Irish Scientists Highlight Incidence of E. coli O157:H7 Food Poisoning in Ireland

One beef burger in every one million consumed at home in Ireland could, in theory, cause serious E. coli O157:H7 food poisoning, Teagasc and University College Dublin researchers have concluded.

While this incidence is relatively low, the severity of illness caused by E. coli O157:H7, indicates that this risk needs to be lowered even further to protect the consumer.

A scientific team led by Dr Geraldine Duffy, Head of the Food Safety Department at Teagasc's Ashtown Food Research Centre in Dublin, have developed a quantitative risk assessment computer model to predict the risk to the Irish consumer from E. coli O157:H7 in beef burgers prepared and consumed at home. Other members of the team were Dr Stephen O'Brien of Teagasc, Dr Francis Butler, Dr Enda Cummins and Dr Padraig Nally of UCD.

E. coli O157:H7 is a serious food poisoning bacteria that can cause a range of symptoms from bloody diarrhoea to kidney failure. Young children and the elderly are most susceptible to severe forms of the illness and as few as 10 to 100 bacteria may cause illness in susceptible individuals.

Cattle and beef are recognised as a significant source of E. coli O157:H7. Research on the prevalence and number of E. coli O157:H7 in beef presented for slaughter in Ireland showed that 7.3 percent of cattle had the bacteria on their hides and 2.5 per cent had it in their gut. The bacteria isolated in this study were all shown to have the virulence factors potentially needed to cause illness in humans.

Based on this data, the developed computer model predicted whether each stage during slaughter, processing, retail and domestic storage, and home preparation and cooking would increase or decrease the number of bacteria. It was this computer model which predicted the potential exposure of consumers per serving of beef burger to food poisoning.

"The computer model also indicated that the best way to reduce the risk from E. coli O157:H7 in beef would be to reduce the level of the bacteria on the hides of cattle presented for slaughter, to strictly maintain chill storage temperatures in retail outlets and at home and, most importantly, by cooking beef burgers to a well done state," Dr Duffy concluded.

"It should also be recognised that beef is not the only source of E. coli O157:H7 food poisoning, lamb, unpasteurised dairy products, vegetables or salads grown in contaminated soil, and contaminated water may also cause illness", she said.