Salmonella risk from damaged salad leaves

BROKEN leaves in bags of prepared salad may dramatically increase the risk of salmonella, a study has shown.

Juice from damaged leaves can boost growth of the food poisoning bug more than 2,400-fold, scientists discovered.

It also raises the chances of the bacteria causing an infection.

Experts warned consumers to avoid ready-cut salad, to rinse bagged salad thoroughly, and not to let it get warm. The scientists investigated the way the bacteria grew on damaged leaves and attached itself to plastic bag surfaces.

Cos, baby green oak, and red romaine lettuce, spinach, and red chard obtained from commercially available bag mixes were all used in the tests.

The trials showed that juice from broken leaves increased salmonella growth in water by 110 per cent. When the juice was added to a nutrient medium supporting salmonella, the bacteria’s growth rose more than 2,400-fold.

Lead scientist Dr Primrose Freestone, from the University of Leicester, stressed “the need for salad leaf growers to maintain high food safety standards as even a few salmonella cells in a salad bag at the time of purchase could become many thousands by the time a bag of salad leaves reaches its use by date, even if kept refrigerated”.

The research was published in the journal Applied and Environmental Microbiology.