Novel technology uses visible light to clean surfaces and preserve food

News > World

By STEM Caribbean | Posted on July 21, 2020

A company in Singapore has developed an innovative technology that can continuously clean surfaces using visible light instead of chemical cleaning agents.
Image by Couleur from Pixabay

Good hygienic practice is one of the shortcomings across the world revealed by the COVID-19 pandemic. This unprecedented wake-up call has inspired research and the invention of technologies to enhance how we clean our surroundings. One company called SafeLight in Singapore has developed an innovative technology that can preserve food and continuously clean surfaces using visible light. 

Dr. Vinayak Ghate, a Research Fellow at the National University of Singapore (NUS) who specialises in visible light disinfection, describes the technology in a newsletter published by the university. He says that the technology he and his team developed “can kill a variety of microorganisms continuously and safely.”  

Current cleaning methods commonly used involve manual periodic disinfection methods, which are not always effective as surfaces could become contaminated immediately after being cleaned. Also, contaminated surfaces can spread germs, especially surfaces that are frequently used by humans.   

“Currently, the typical way that these surfaces are disinfected is via manual cleaning with chemicals, ultraviolet (UV) light, and hydrogen peroxide vapours (in a hospital setting) or ozone vapours (within the food industry),” says Dr. Ghate.  

Although these methods may seem practical for cleaning, they pose some challenges.   

“However, these disinfection methods are either unsafe to be used around human presence or impractical for businesses to implement continuously. Hence, they end up being ‘episodic’ affairs,” Dr. Ghate adds.  

The technology developed by Dr. Ghate and his team involves a principle known as photodynamic inactivation (PDI), which targets substances sensitive to light that are naturally present in microbial cells such as bacteria. The substances trigger toxic chemical reactions when exposed to light, eventually killing the cells.  

“PDI opens up the possibility of continuous disinfection because the antimicrobial action can be achieved using visible light, which is perfectly safe for humans,” Dr. Ghate states.  

He also notes that in contrast, UV light, which is more commonly used, is not as safe as visible light for continuous use.   

Research on this technology began over five years ago with the then Assistant Professor Hyun-Gyun Yuk and Professor Zhou Weibiao of the Food Science & Technology Programme (now Department of Food Science & Technology) overseeing the research at the NUS.   

The research team studied the effect of light-emitting diodes (LEDs) on bacteria and published the results in the peer-reviewed scientific journal, ScienceDirect. The study showed that LEDs had the potential to be used in food preservation.  

SafeLight was later formed from this research and is supported by the NUS. The company is developing devices for businesses to improve their hygienic practices.  

“Depending on the business, this could lead to benefits such as lower re-hospitalisation rates (healthcare), longer product shelf-life (food processing) and enhanced brand reputation (hospitality),” says Dr. Ghates.  

Although continuous disinfection technologies are still in the early stages, the COVID-19 pandemic has proven than these technologies are likely to become more common in the future, according to Dr. Ghates.  

“Given how COVID-19 has highlighted the limitations of episodic methods, it is a matter of when, not if, continuous disinfection will be the new standard,” he notes. 



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