Watermelons link to salmonella outbreak

2nd February 2012 - Watermelons could be behind an outbreak of a strain of Salmonella Newport among 34 people in the UK.

The Health Protection Agency (HPA) has begun an investigation into the outbreak which has claimed the life of one person.

Cases of the infection have also been reported in Ireland and Germany.

The Newport strain

Salmonella Newport causes a similar illness to other types of salmonella infection. Symptoms include:

• Diarrhoea
• Vomiting
• Abdominal pain
• Fever

Most cases resolve within four to seven days but some people may need a course of antibiotics. Complications can include blood poisoning (septicaemia), or a localised infection such as septic arthritis.

Among 30 cases in England, Wales and Northern Ireland, ages of those affected ranged from six months to 85 years. The person who died also had serious underlying health complications, the HPA said. Women accounted for 70% of all cases and the East of England has been particularly badly affected.

There have been four confirmed cases in Scotland, five in Ireland and 15 in Germany.

Watermelons

Although the investigation into the outbreak is at an early stage, the HPA said watermelons were the most likely cause.

In November 2011, as part of a local food survey, the HPA identified Salmonella Newport from a ready-to-eat sliced watermelon. Subsequently, a number of people who became unwell were found to be infected with the same strain of Salmonella Newport identified in the watermelon sample taken during the survey.

All the 30 people in England, Wales and Northern Ireland in the current outbreak were infected since early December last year. In addition, 10 of 15 cases which have been followed up by telephone said that they had eaten watermelon in the three days before they felt unwell.

In a statement, Dr Bob Adak, head of the gastrointestinal diseases department at the HPA said: “Although it’s too soon to say with certainty what the likely cause of infection is, early indications suggest that a number of people became unwell after eating watermelon. This has also been noted in the cases in Scotland and Germany although further investigation is ongoing."

Food hygiene

Experts say there are two ways that Salmonella Newport could have contaminated the watermelons. Either the surface of the melons could have been contaminated, and this may have transferred onto the flesh of the melon during the cutting process. Alternatively, if the melons were stored or washed in contaminated water, the Salmonella bacteria could have got into the flesh of the melon through the cut stem.

Alison Gleadle, director of food safety at the Food Standards Agency said consumers would be alerted about the cause of the outbreak as soon as more information came to light. "In the meantime, it’s important for people to follow sound food hygiene practice when preparing any food," she said in a statement. "It is always advisable to wash fruits and vegetables before consumption to reduce the risk of possible illness."

There have been previous outbreaks of Salmonella Newport in the UK. The largest one was in 2004 and was associated with the consumption of lettuce at restaurants and takeaways.