Washing Veggies May Not Get Rid of Bacteria

Washing vegetables may not be enough to banish dangerous bacteria hiding inside their leaves, warn scientists.

Tests show only a commercial process using radiation was successful at eradicating the bugs that can cause food poisoning from contaminated lettuce and spinach.

Even disinfecting the vegetables with chemical agents was not completely effective, according to a report from a team in the U.S.

Although washing fresh produce before eating is known to reduce the risk of food poisoning, there have long been doubts about its total effectiveness.

Microbes such as salmonella and E.coli may elude water and chemicals by burrowing into leaves.

They can also seek safety in numbers by organising themselves into tight-knit communities called biofilms, which stick to the surfaces of fruits and vegetables

The scientists found washing with plain water did little to reduce levels of E.coli in either spinach or lettuce.

The chemical treatment, a sodium hypochlorite solution, did not significantly reduce bacteria numbers in spinach and wiped out fewer than 90 per cent of the bugs in the lettuce samples

Radiation, on the other hand, significantly reduced levels of the bacteria in both spinach and lettuce

At the highest radiation dose, 99.99 per cent of the germs in lettuce and 99.90 per cent in spinach were killed.