How many times have you skipped work due to food poisoning? And throughout the day, you keep wondering, “Was it the burger from McDonald’s or was it KFC’s bucket chicken?” The real culprit was the week-old sausage from your fridge. But how could that be? Clearly, the barcode sticker on the sausage wrap mentioned a later expiry date alongside a ‘promise’ that they are safe for consumption as long as they are refrigerated. And you believed in that ‘gospel truth’ of marketing.
Now, we could put an end to this culinary dilemma. South Korean scientists have created a laser that could detect bacteria in refrigerated food. Researchers from Korea Advanced Institutes of Science and Technology have found a quick-fix way to spot bacteria on the surface of foods in just a few seconds.
According to MIT Technology Review, this technique could be easily used in food processing lines and even fitted to standard home fridges.
The laser technique is quite simple. Bacteria such as salmonella have hair-like flagella that they use to propel themselves across surfaces. This movement turns the surface of contaminated food into an ocean of writhing microorganisms. When a red, coherent laser beam hits biological tissue, it is scattered through the material. This scattering causes the light to interfere, creating a random pattern called laser speckle, according to the research paper by Jonghee Yoon, KyeoReh Lee and YongKeun Parksay Yoon.
All that is needed to monitor this change is a camera that can record the change over a few seconds. The team used one that takes images at a rate of 30 times a second and then process the images by subtracting one from another to reveal any difference.
Equipment is not expensive
The equipment is not expensive. It can be easily installed in your home refrigerators.
Of course, there are limitations. Though the laser helps detect different types of bacteria, it cannot distinguish between them. And of course, it cannot spot contaminants that do not change the laser speckle over time. So it wouldn’t pick up viral contaminants, such as norovirus, which is responsible for over five million causes of food-borne illness. Neither does it detect the toxins produced by bacteria, which can cause illness even when the bacteria have been killed off.
Nevertheless, the new technique has the potential to significantly improve food hygiene and thereby reduce the number of cases of food poisoning each year.