Super strong bactericidal effect LED or will enter the fresh market

The best condition for using this method is the weak acid environment of pH 4.5 at 4-15, the scientists say. Acidic food, such as fresh cut fruit and instant meat, can be kept fresh without further chemical treatment in a low temperature and blue LED environment.

Although LED is usually used as a source of energy saving, they also have bacteriostasis. The cells in bacteria contain light sensitive compounds that absorb the visible part of the electromagnetic spectrum (400-430 nanometers) and this part is mainly blue LED light. Exposure to blue light LED causes a series of reactions within the cell, which eventually leads to its death.

In the past, the research on the Bacteriostasis of LED was mainly by adding photosensitizer to the food sample, or in the case that the distance of the light source was very close (less than 2 cm). These conditions can not be truly applied to the preservation of food. Scientists from National University of Singapore have shown for the first time how food related factors such as temperature and pH value affect the bacteriostasis effect of LED light.

The research team placed three main source of food source pathogens, Lester monocytogenes (Listeria monocytogenes), Escherichia coli O157:H7 (Escherichia coli O157:H7) and Salmonella typhimurium (Salmonella Typhimurium) under blue light LED, and adjusted them to different acids and bases respectively.

The results showed that the bacteriostasis effect was better than neutral under the condition of acid or alkaline. The acid condition has more inhibitory effect on Lester bacteria, but for Escherichia coli O157:H7 and Salmonella typhimurium, the alkaline environment is the best, but the acid environment can also be effectively inhibited. A 2013 study by the research team found that blue light LED has the strongest inhibitory effect on bacteria at low temperatures.

"Combining these results, we found a possible way to preserve acidic food at low temperatures," said Professor Yuk Hyun-Gyun, the research director. This may meet the growing demand for natural food, without the need for chemicals such as acid and artificial preservatives to preserve food. "

These findings have a potential value for food preservatives and food supplies, which are used to preserve fresh fruit and instant seafood such as sushi and smoked salmon and cold meat products. The technology can also be used for retailers such as gourmet streets and supermarkets.

"Next, we want to apply this LED technology to real food samples, including fruit, seafood and meat, to see if the pathogen can be effectively killed without damaging the food," Yuk said. The team was also studying using LED technology to keep fresh or to increase the nutrients in the storage of vegetables.

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