SOFHT focus on E.coli By Harold Ackroyd, Council representative for legislation. From SOFHT Focus 21 1997
Although the food industry has been familiar with E.coli organisms for many years, it is only recently that the public at large has become aware of their existence. This is no doubt due to the publicity following outbreaks of E.coli 0157 in Scotland.
Food technologists, environmental health officers and food handlers look upon E.coli as an organism, which is indicative of poor food hygiene practices when found in food. It can indicate cross contamination between raw and cooked foods, or a failure by food handlers to wash their hands after a visit to the toilet.
E.coli is a common inhabitant of the gut of both animals and people. There are many types of E.coli, most of which are harmless. Unfortunately, the E.coli 0157 type produces a toxin which can cause serious illness in people. It has recently received widespread notoriety following several outbreaks in the UK and in particular one major outbreak in Scotland, which resulted in the deaths of 20 elderly people.
Only a small number of E.coli 0157 organisms are required to cause illness. They produce a potent toxin which enters the blood stream and can result in acute renal failure. It can prove fatal to vulnerable groups of people, particularly the elderly, the young and the already infirm. The symptoms of this infection are wide ranging, starting with non-bloody diarrhoea, abdominal pains and cramps, followed within one to three days by grossly bloody diarrhoea and anaemia. The symptoms can be so severe as to expose the patient to the risk of unnecessary surgery such as hemicolectomy (removal of part of the colon).
Outbreaks
Currently, E.coli 0157 infections are more prevalent in the USA, Canada and the UK, than elsewhere in the world. This may be due to these countries having better developed techniques for identifying the organism than other countries. However, outbreaks and sporadic cases have also been reported in Argentina, Australia, Belgium, China, Czechoslovakia, Italy, Japan, Korea, New Zealand, Romania, Spain, and Thailand.
The first documented outbreak occurred in the USA, in 1982, and involved 47 confirmed cases of E.coli 0157. There was a strong epidemiological association between this outbreak and the prior consumption of beef from a fast food chain. The organism was also isolated from beef patties from one of the suspect outlets.
Thirty-five children affected in an outbreak in the West Midlands between 1982-1983 resulted in 23 needing renal dialysis, three deaths and nine developing chronic renal failure.
Photo courtesy of Meat Hygiene Service
It is difficult to define a seasonal pattern for this infection, with different countries experiencing peaks at different times. In Canada, it occurs more commonly from mid-summer to mid-autumn, a period when many people hold barbecues. This may suggest the consumption of undercooked meat. In the UK, outbreaks are more common in mid to late summer. Here again, meat is the most likely source, but other sources may include seasonal fruits and salad vegetables grown on land which has been spread with untreated manure.
Unchlorinated water supplies and untreated milk have also caused outbreaks. One such outbreak involved children in South Yorkshire who consumed untreated milk. Two outbreaks in the USA were caused by freshly pressed, unpreserved apple cider and the number of other foods involved continues to increase.
Background to E.coli 0157
E.coli 0157 was first isolated from diarrhoeal cattle in Argentina in 1977. Since then tests have also found the bacterium in lamb but, surprisingly, only rarely in pork, pork products and poultry. E.coli 0157 organisms are quite susceptible to heat, therefore, thorough cooking of contaminated meat will make it safe. Unfortunately foods eaten raw and cooked ready-to-eat meats are always susceptible to cross contamination.
Resent research results
A report published in June this year by scientists at the Centre for Applied Microbiology and Research (CAMR) suggests that E.coli 0157 is so persistent in the environment that new practices on the farm and in the kitchen may be necessary to contain its spread.
Laboratory tests undertaken at the Porton Down facility have shown that the bacterium can survive in animal faeces for months, indicating that farmers might have to wait longer before introducing uninfected cattle into fields that have previously contained infected cattle.
Scientists also found that E.coli 0157 can survive easily for two months when left on dry stainless-steel work surfaces, emphasising the need for stringent cleaning procedures within the food industry. A strong bleach solution would be an effective disinfectant, they said.
Photo courtesy of Meat Hygiene Service
Effects of E.coli on the food industry
The rising incidence of E.coli 0157 infections presents serious consequences for the food industry. Following blanket coverage by the media of cases by this organism, people are now concerned about the safety of their food supply. The outbreak in Scotland involving a butcher's business alerted many to the dangers of cooked meats which have not been properly handled in shops dealing in raw and cooked meats.
Many butchers running small family businesses are bewildered by events. Many still quote the age-old maxim "but we have always done it this way and have never made anyone ill". However, many hitherto food-borne illnesses, which were never investigated, are now more likely to be reported and the cause of the illness identified.
Pennington group report
Following the Pennington Group's final report, the food industry awaits with bated breath the Government's final reaction to its recommendations. The implications of selective licensing of premises, introduction of documented hazard analysis systems, separation of raw and cooked meats and the call for more training for food handlers will all add to the costs of producing, wholesaling and retailing meat products.
Although the small business operators will be particularly hard-hit by the proposals, supermarket chains will also need to review their operations. Many have separate counters for their raw meats but have staff serving cooked meats and cheese as well as sausages and bacon. If this system is to continue, staff must be supervised to ensure that they wash their hands after touching raw meats.
Farm workers and slaughterhouse personnel must make sure that they play their part in cleaning up meat. Dirty animals must not be sent or admitted to slaughterhouses. Care must be taken by farmers who spread slurry and manure.
However, although the Pennington Group report directs its attention at the meat industry, this is only part of the equation. In fact, many other premises are involved in processing and retailing meat including catering establishments.
The report also recommends an increased frequency of inspections at retail outlets dealing in raw and cooked meats. This, along with the time spent advising management in the concepts of HACCP, will place a greater strain on local authority resources.
There is no doubting the seriousness of the emergence of E.coli 0157 to both the consumer and food industry. Careful and sensible decisions are now necessary by Government and their advisors when deciding the way forward.
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