Salmonella strain hits take-aways
by Nigel Bartlett
Take-away meals are a prime source of a virulent new strain of salmonella, according to a report from the Government's Public Health Laboratory Service (PHLS).
Salmonella typhimurium definitive type 104 was first identified in 1984. Cases rose slowly until 1990, when they started increasing rapidly, reaching about 1,600 cases in England and Wales in 1993.
As a result, the PHLS carried out research to discover whether the increase was due to the consumption of specific food items or other factors.
The researchers found certain foods were particularly associated with the salmonella strain, including chicken, pork sausages and sausage rolls in restaurants and take-aways.
Their findings, in the latest issue of the service's Communicable Disease Report, indicate that chicken cooked at home has a lower risk of being contaminated, which researchers conclude could be because of improved practices among householders.
The higher risk of food from restaurants and take-aways could be a result of contaminated supply, cross- contamination, under-cooking, or a combination of all three, according to the report.
It points out, however, that other transmission routes are significant, such as contact with sick farm animals and pets.
The Ministry of Agriculture, Fisheries & Food is investigating infection in cattle. This strain of salmonella typhimurium has so far proved resistant to antibiotics, which the PHLS believes may be due to the use of antibiotics in animal feed.
Ironically, though, it appears one source of infection is feed that contains cereal or by-products of meat-processing infected with salmonella typhimurium. Stress and crowding during transport can increase the spread of infection.
The researchers looked at 83 cases of the salmonella typhimurium strain between 1 September and 12 November last year. Some 34 of the cases had involved admissions to hospital. Ten people died from infection during the period of the study.
