Listeria is one of several dangerous food-borne bacteria that are threatening us every day we shop for groceries. While it normally affects only about 1,600 Americans yearly, it can be deadly even if treated in time. The challenge for food producers is to eliminate listeria, and other deadly pathogens, from food before they come to our plate. Researchers and engineers from Rensselaer Polytechnic Institute came up with a new innovative method of killing harmful bacteria, including listeria, in food packaging and handling. This new method offers an alternative to the antibiotics and chemicals that are currently used for food decontamination, often ending up as part of our meal.
How serious is listeria?
Regardless of the relatively small number of people that get infected by listeria, CDC considers the treat very seriously. The last big outbreak in 2002 was caused by contaminated turkey deli which affected 54 people, eight of them fatally. In 2012, imported ricotta cheese was infected with listeria, infecting 22 people of which four died.
Listeriosis, the disease caused by listeria, affects primarily older people, pregnant women, babies and people with compromised immune systems.
The most common symptoms of listeriosis are: fever, muscle aches, headache, stiff neck, convulsions, diarrhea and other stomach problems. In almost all cases, the bacteria spread from the gastrointestinal tract to other parts of the body. The disease is particularly dangerous for pregnant women, who in many cases lose the baby or have premature delivery.
Scientists from the Rensselaer Polytechnic Institute combined two innovative approaches to attacking listeria: one is the use of nanoparticles, and other is the use of cell lytic enzyme.
The researchers attached cell lytic enzymes to FDA- approved silica nanoparticles, and made a fine coating able to selectively destroy listeria. This powder coating kills listeria on direct contact, even when in very high concentrations, almost instantly, without having any effect on other bacteria. Another option the scientists explored was to attach the lytic enzymes to starch nanoparticles, which are commonly used in many food packaging materials.
Scientists believe that they can use the same method, but with different lytic enzyme, to target other dangerous bacteria, such as anthrax.
Results of the study were published in the Scientific Reports journal, a publication of the Nature Publishing Group.