Super bactericidal effect of LED or will enter the fresh market

The best condition for the use of this method is the weak environment of pH 4.5, 4-15 scientists said. Just cut fruit and ready to eat meat and other acidic foods in the low temperature and blue LED environment, without further chemical treatment can be fresh.

Although LED is usually used as an energy-saving light source, they also have antibacterial effects. The bacterial cells contain light-sensitive compounds that absorb the visible part of the electromagnetic spectrum (400-430 nm), which is mainly blue LED light. Exposure to blue light LED triggers a series of reactions within the cell, which ultimately leads to death.

In the past, the study on the inhibition of LED light was mainly through the addition of photosensitizer in food samples, or in the light source is close to the distance (less than 2 cm) to verify the effect. These conditions cannot be used in food preservation. Scientists from the National University of Singapore have shown for the first time the effects of temperature, pH and other food related factors on the inhibitory effect of LED light.

The research team will be three major food sources of pathogens -- Lester (Listeria monocytogenes) bacteria and Escherichia coli O157:H7 (Escherichia coli O157:H7) and Salmonella typhimurium (Salmonella Typhimurium) in blue LED, and were adjusted to different pH values.

The results showed that under acidic or alkaline conditions, the inhibitory effect was better than neutral. Acidic conditions were more potent against Lester, but the alkaline environment had the best effect on Escherichia coli O157:H7 and Salmonella typhimurium, but the acidic environment could also be effectively inhibited. A 2013 study by the team found that blue LED had the strongest inhibitory effect on bacteria at low temperatures.

"Combining these results, we found a possible way to preserve acidic foods without chemical treatment at low temperatures," said Hyun-Gyun, an associate professor at Yuk. This may satisfy the growing demand for natural food without the use of chemicals such as acid and artificial preservatives to preserve food. "

These findings have potential value for food storage cabinet and food supply for fresh cut fruit, ready to eat seafood such as sushi and smoked salmon and cold meat products. This technology can also be used for retailers, such as gourmet street and supermarket.

Yuk said: "the next step, we hope to apply the LED technology to real food samples, including fruits, seafood and meat, to see if it can effectively kill the bacteria without destroying the food. "The team is also working with LED technology to preserve or increase the amount of nutrients stored in vegetables.

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