Microbiology confirms a bean sprout link with Salmonella Bareilly cases

7 October 2010

Microbiologists at the Health Protection Agency’s Centre for Infections (CFI) in Colindale have confirmed the link between contaminated bean sprouts and 141 cases of Salmonella Bareilly in the UK.

Specialists in the CFI’s Salmonella Reference Unit report that the strain of Salmonella Bareilly isolated from a bean sprout sample is indistinguishable from the strain of S. Bareilly isolated from human samples.

Bean sprouts had already featured strongly in a case control study in which people who had suffered from S. Bareilly infection and controls (people who did not become ill) were questioned about what they had eaten prior to the onset of illness.

However, both the HPA and the Food Standards Agency (FSA) stress that bean sprouts are safe to eat provided that they are washed and cooked until piping hot before consumption or are clearly labelled as ready-to-eat.

Professor Qutub Syed, a director with the HPA’s Local and Regional Services Division, is chairing an outbreak control team comprising representatives from the Agency, the FSA, Health Protection Scotland and Environmental Health Officers from a number of local authorities.

Professor Syed said: “As time went on our investigations produced increasingly strong evidence of an association with bean sprouts in this outbreak. Now we have results from microbiological sampling to corroborate the findings of the epidemiological studies. The link with bean sprouts has been established.

“However, no one should be put off eating bean sprouts, provided they are properly cooked. The risk is in eating raw or under-cooked bean sprouts. The best advice is to follow the guidance on the packaging, but if there is any doubt or ambiguity about the instructions, cook the sprouts until they are piping hot.”

Professor Syed added that people who prepare meals in catering establishments and in the home should keep raw bean sprouts separate from other salad products, including ready-to-eat bean sprouts, to avoid the risk of cross-contamination. The FSA advice on the safe preparation of bean sprouts may be accessed on http://www.food.gov.uk/.

Information on salmonella is available on the HPA website www.hpa.org.uk

Notes to editors

Salmonella

Salmonella bacteria are commonly found in the gastrointestinal tracts of wild and domestic animals and birds, especially poultry, and occasionally in humans. Salmonella Bareilly causes gastro-enteritis in humans through consumption of contaminated food.

Infection with Salmonella can cause watery and sometimes bloody diarrhoea, abdominal pain, headache, nausea, vomiting and fever.

Illness can range from mild to severe. The elderly, infants, and those with impaired immune systems are more likely to have severe illness. In some cases, infection may spread from the intestines to the blood stream and then to other body sites and can be fatal without treatment. However, death from Salmonella infection is rare.

Salmonella infection frequently results from contact with contaminated food products; the cross-contamination of cooked food by raw food; and/or a failure to cook food properly. Contact with infected animals may also result in human infection. Person-to-person spread can occur, particularly during the diarrhoeal phase of illness.

Treatment

The majority of patients with salmonella infection recover without treatment. Recovery is aided by the replacement of fluids. The advice of a health professional should be sought in cases of severe diarrhoea.

In rare events when infection spreads from the intestines to the blood stream, prompt hospital treatment with appropriate antibiotics is required.

Prevention

Salmonella can be prevented by the correct storage and cooking of foods and by hygienic food handling and preparation. Avoidance of certain foods, for example unpasteurised milk and dairy products and raw eggs will also lower the risk of illness.

It is important for people with symptoms to maintain their fluid levels and take the utmost care with hand-washing and hygiene generally. It is especially important for people to wash their hands before eating or preparing food, after handling raw meat or poultry, after using the toilet, after changing nappies and after cleaning up after others with diarrhoea. Hand-washing after contact with domestic or farm animals is essential. Children who have touched animals should be supervised when washing their hands.

Press release issued by Hugh Lamont, Regional Communications Manager, HPA North West. For further information please call Hugh Lamont on 0151 482 5728/07764 906508 or the national HPA press office on 0208 327 6647/7098/7097.

Last reviewed: 7 October 2010