Posted by Neelam Goswami on September 03, 2008

More and more people nowadays tend to buy pre-packed salads as it is a great timesaver in the kitchen, but findings from a latest research suggest these salads actually are unsafe to eat.

The new research warned today that pre-bagged salads could lead to an increase in food-poisoning cases, so consumers should be aware of the risks when buying ready-washed greens.

Led by Professor Gadi Frankel from Imperial College London, the research looked into the food contamination. The research, presented today (Wednesday) at the 21st International ICFMH Symposium 'Food Micro 2008' conference in Aberdeen, details how Salmonella and E.Coli bacteria can contaminate salad leaves.

Prof. Frankel said as cases of food poisoning are expected to increase in coming years, the comprehensive understanding of how the aforementioned bacteria virus can contaminate salads becomes more important.

"If we can find out what factors affect susceptibility, we may be able to develop new technologies to harness the 'immunity' found in some salad leaves to protect others from contamination," he says.

Salmonella infection causes short term effects like nausea, vomiting, fever, diarrhea as well as abdominal cramps. However, in young children, the elderly and people who have a weak immune systemdefine, salmonella may cause serious and sometimes deadly infections. Long-term complications may include severe arthritis.

One of the chief culprits behind food borne diseases, Escherichia coli O157:H7 was first discovered in 1982. E. coli is known to release a deadly toxin that causes the disease. It spreads through ground beef, bean sprouts and leafy vegetables and is characterized by the symptoms of stomach cramps, dehydration and bloody diarrhea. The infection generally clears up in 5 to 10 days time.

However serious infection is known to cause kidney failure and hemolytic uremic syndrome (HUS), a disease that affects mostly children under the age of 10, but also may affect the elderly as well as persons with other illnesses.

Prof. Frankel said that pre-packed salads were blamed to be the source of two recent outbreaks in the United States and United Kingdom. Last year, a salmonella outbreak in the UK was caused by imported basil, and in 2006, an E coli outbreak in the United States was traced to pre-packed baby spinach.

Prof. Frankel said: "People are eating more salads, choosing to buy organic brands and preferring the ease of 'pre-washed' bagged salads from supermarkets, than ever before.”

"All of these factors, together with the globalisation of the food market, mean that cases of salmonella and E coli poisoning caused by salads are likely to rise in the future," he continued.

Frankel said his team would now try to determine the factors that made some salad leaves less susceptible to salmonella bacteria that attacks the stomach and intestines.

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