Washing fresh fruits and vegetables before eating may reduce the risk of food poisoning, but it is not enough to deter nasty little microbes.
These microbes sneak in and make themselves comfortable inside lettuce leaves, spinach and other vegetables, beyond the reach of surface treatment.
Microbes form tightly knit communities called bio-films that coat fruits and vegetables and protect them from harm. This conspiratorial community harbours deadly specimens like E. coli and Salmonella, multiple infections by other names.
However, findings by scientists of US Department of Agriculture indicate that irradiation remains a promising technique that inactivates parasites and destroys pathogens and insects in food, including E. coli and Salmonella.
These findings were presented Thursday at the 235th national meeting of the American Chemical Society.
Researchers conducted tests with biofilms to see how different strains of Salmonella and E. coli, buried inside them, stood up to irradiation. Bio-films concealing Salmonella tended to die more easily with irradiation, while those that were infected with E. coli were a bit more resistant.
The technique could provide a reliable way to reduce the numbers of food-borne illnesses reported every year, said Brendan A. Niemira, who directed the study.
“When bacteria are protected – whether they’re inside a leaf or inside a bio-film – they’re not going to be as easy to kill,” Niemira said. “This is the first study to look at the use of irradiation on bacteria that reside inside the inner spaces of a leaf or buried within a bio-film.”
“Sixty to 90 percent of consumers indicate that they would buy irradiated food when told about its benefits and the endorsement of health authorities,” said Christine Bruhn of the University of California.