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Lasers speed up detection of bacteria in packaged food

The device combines a series of laser diodes and optical sensors.
By Brooks Hays   |   March 16, 2016 at 3:36 PM

JINHUA, China, March 16 (UPI) -- The wrong type of bacterial growth in packaged food can poison consumers.

Monitoring bacterial growth isn't easy, but researchers in Sweden and China have collaborated to create a laser-powered device that accurately monitors microorganisms in food and blood supplies.

Currently, food producers rely on a relatively short shelf life to ensure their products don't go bad as a result of pathogenic microbes. Researchers say an improved understanding and monitoring of bacterial growth could diminish food waste.

"Microorganism growth is always associated with the production of carbon dioxide, CO2," researcher Jie Shao, associate professor with the Institute of Information Optics at Zhejiang Normal University, in Jinhua, China, said in a news release. "By assessing the level of CO2 within a given closed compartment -- bottle or bag -- it's possible to assess the microbial growth."

The new device, which consists of series of laser diodes and optical sensors, improves on previous technologies by achieving very low detection limits of CO2.

"The emission wavelength of the laser is tuned over a characteristic absorption line transition -- of the species within the gas being assessed," Shao explained. "This causes a reduction of the measured signal intensity, which we can use to determine the gas concentration."

The extra-sensitive laser allows bacterial growth in packages of food or biological samples to be quickly and accurately measured.

The new detection device is described in a new paper published in the journal Applied Optics.

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