Watermelons are being blamed for causing widespread salmonella poisoning following a deadly outbreak across the UK which has so far affected 35 people and led to one death.

There are 2,500 different strains of salmonella but the latest outbreak is caused by a strain called Salmonella Newport and health experts believe that watermelons are the main culprit.

The Health Protection Agency (HPA) has revealed that 35 people in England, Wales, Scotland and Northern Ireland have been infected since December, which is three times higher than the normal number of cases expected in a two-month period. The average number of salmonella cases a year in the UK is usually around 200.

Watermelon is being blamed for the latest outbreak after the HPA identified the Salmonella Newport strain in ready-to-eat sliced watermelon imported from Brazil last November.

Subsequently, a number of people fell ill with the same strain that was identified in the HPA study. Since this discovery, the HPA has spoken to 15 of the affected people and found 10 had eaten watermelon in the three days before they become ill.

There are two possible ways that watermelons could become contaminated with Salmonella Newport.

Firstly, the surface of the fruit could have been contaminated with salmonella bacteria and this would have easily been transferred onto the flesh of the melon during the slicing process.

Secondly, the watermelons could have been washed and stored in water that has been infected with Salmonella, which could then sink into the flesh through the stem of the fruit.

Symptoms of salmonella include diarrhoea, vomiting, abdominal pain and these usually appear within 72 hours after eating a contaminated food product. For most people, the symptoms wear off between four to seven days.

However, health watchdogs are warning that elderly people and very young are most at risk of suffering implications like septicaemia (blood poisoning) or septic arthritis.

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.

"It's important to remember the risk of becoming unwell after eating watermelon is very low."

The Foods Standards Agency (FDA) has been involved in the investigations and said it will be monitoring the situation and working closely alongside the European commission, as it’s not just occurring in the UK - five cases have been reported in Ireland and 15 in Germany.