Hot dogs, deli meats and other processed meats can harbour Listeria monocytogenes, which causes 2500 cases of food poisoning and 500 deaths in the US each year. But a novel packaging film made from renewable materials such as corn residues could stamp out Listeria and other food-borne bugs.
Tony Jin at the US Department of Agriculture in Wyndmoor, Pennsylvania, created a biodegradable polylactic acid (PLA) film containing a natural antimicrobial agent called nisin.
When Jin spiked orange juice and egg whites with Listeria, E. coli O157:H7 and Salmonella enteriditis, and placed them on the film, it killed significant numbers of bacteria (Journal of Food Science, ).
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Jin plans to make a nisin/PLA film for wrapping meats and a liner to coat the insides of drinks containers. He is also testing another film made from nisin and pectin, better known for thickening jams and jellies. A pectin-based wrapper would be edible.
The US Food and Drug Administration declared nisin a safe ingredient 20 years ago, and it is sometimes added to processed foods to kill bacteria in the short term. Lacing PLA with nisin would extend its killing power.
