Packing ready-to-eat vegetables

Ready-to-eat vegetables, including pre-packaged greens for salads, have a short shelf life and are most often eaten straight from the package without the need for cooking.

That means they are a prime place for foodborne pathogens " such as listeria and E.coli " to grow.

Dr Jaejoon Han, Texas A&M University, wanted to determine ways to prevent foodborne illnesses by killing the pathogens before they could contaminate foods.

His research group worked with the electronic beam irradiation, a form of non-thermal food processing that does not alter the quality attributes of the fresh product, combined with the use of packaging material that had been coated with a natural antimicrobial agent. Packing vegetables in plastic bags coated with a natural antimicrobial agent and then processing them under electronic beam irradiation was found to reduce amounts of foodborne pathogens.

Han put the romaine lettuce inside the plastic bag and applied irradiation energy and found the microbial growth was greatly suppressed. Also, the colour and texture of the lettuce were not damaged by the irradiation.

Both the plastic packaging and the antimicrobial agent Han used have been approved by the US Food and Drug Administration.