DUBAI // Every sample of rocket salad leaves tested from 64 shops in Dubai and Sharjah was contaminated with high levels of potentially deadly E. coli bacteria, researchers have found.
The leaves - also called jarjeer, or arugula - came from outlets ranging from small stores to large supermarket chains. Millions of faecal coliform cells and hundreds of thousands of E. coli bacteria were found in samples of one gram, about the size of a small leaf.
Ten cells of some E. coli strains are enough to cause illness, especially in children. The bacteria can cause diarrhoea, dehydration, respiratory problems, urinary tract infections, pneumonia and other illnesses. Some strains can be deadly.
The samples were analysed by Dr Dennis Russell, a researcher at the American University of Sharjah. After washing the leaves three times he still found hundreds of thousands of viable faecal coliform microorganisms per gram, and thousands of E. coli bacteria.
Washing with diluted chlorine bleach did not remove the bacteria.
Dr Russell's research is published in the current issue of the Egyptian Academic Journal of Biological Sciences.
Dr Tibor Pal, a professor of microbiology and immunology at United Arab Emirates University, said that although E. coli was not always harmful, high levels indicated faecal contamination and risk of other serious diseases.
"Faecal contamination could mean anything from viruses to parasites, and at high levels is an indication that a food is not suitable for human consumption," he said.
The levels of contamination found in the Dubai and Sharjah samples far exceed the limits imposed in other countries. The United Kingdom and Germany have limits of 100 E. coli bacteria per gram, and Switzerland has a limit of 10 per gram. Brazil has a limit of 100 viable fecal coliform per gram.
Dr Russell said the levels of harmful bacteria he found were higher than in a lavatory. "That sounds sensational, but it's factual," he said. "This food is thousands of times more contaminated."
He said he had been unable to determine where the rocket leaves had been grown - whether they were from UAE farms or imported - but he said he suspected they all came from the same farm or a group of farms that had used liquified raw faeces for fertiliser rather than compost soil.
Other foods tested, such as onions and mint, were also slightly contaminated, but Dr Russell said he was more concerned that the high levels were found on every sample of rocket.
The popular salad ingredient is especially dangerous because it is usually eaten uncooked. It could also be contaminating other food it comes in contact with in shops, he said.
"People have probably been eating this for years and do not realise they are feeling sick because of it, especially if they eat it on a regular basis and in meals with other food," he said.
Aizeldin el Jack, the head of preventive medicine at the Dubai Health Authority (DHA), said the authority would be following up with the municipality to determine how the issue would be addressed.
Officials from the Food Control Department of Dubai Municipality declined to comment. Sharjah Municipality officials did not respond to calls and e-mails.
Mohammed al Reyaysa, a spokesman for the Abu Dhabi Food Control Authority, said officials conduct random tests at local farms but had found bacteria levels to be "acceptable by international standards and the codes of international organisations".
Officials from Dubai's municipality, police and health departments have said in the past that they are working to create a central database for food safety complaints.
The emirate has been developing ways to combat breaches of food safety rules and regulations since two chilcren, Chelsea and Nathan D'Souza, died of suspected food poisoning at a restaurant last year.