By - Papiya Mahanti

“After all it is all of humanity that is under threat during a pandemic.” - Margaret Chan

Cases are again on the rise and experts believe that the second wave will be much worse than the first. Somehow that kind of panic, is not there in the minds of people in spite of repeated warnings by the Government.

Last year during this time, I remember, we were buying nothing other than food and medicines - and of course the masks and sanitizers! The most dangerous trip of the week used to be the trip to the grocery.   I generally tried to minimize these trips and hoard as much as I could on the days on which I would venture out.

News was abuzz with articles on how we could be infected due to ‘what is coming into the house’ because the coronavirus could remain on surfaces for more than 72 hours in some cases. We tried to find ways and means to minimize the risk. Like, we would keep everything in the balcony for three days before putting in the pantry. One reason, I was ready to do anything was that I thought it is a matter of a month or two and then things will get back to normal.

It is March of 2021 and Covid is still very much there. We, somewhere in our subconscious, know that we still need to take precautions but neither the state of panic that was there a year back exists nor the willingness to make that kind of effort, but we all know that we are in dire need of devices that can disinfect surfaces and of course the foodstuff.

During almost the whole of 2020 we were using Lyzol or liquid soap for foodstuff that had plastic wrapping on them. Chemical disinfectants are harmful to human health and mostly they are not that effective as many surfaces are left out during the cleaning process.

A lot of research is underway and LED UVC is emerging as a very promising and viable option for disinfecting surfaces.

Some Researchers from the Tel Aviv University recently claimed that UV C light could kill 99.9% of the coronavirus in less than 30 seconds. The study was published in the Journal of Photochemistry and Photobiology B: Biology.

According to Washington State University food safety specialist Shyam Sablani UV light can be used to kill pathogens on the surface of fruits and vegetables and it is perfectly safe.  Sablani and his colleagues exposed apples, pears, strawberries, raspberries and cantaloupe to different doses of UVC to determine how effective the UVC light was against a mix of strains of E coli and listeria. They found that the light can inactivate up to 99.9 per cent of pathogens on apples and pears.

 The light did not affect the chemical or the physical quality of the fruit used during the study. "If you have smoother skinned fruit, then this technology is really great," Sablani said. "If the fruits are very rough and if the level of contamination is low, it also works quite well," he added. Rough surfaces of strawberries, raspberries and cantaloupe offer places where pathogens can literally hide reducing the effects of UVC light. If bacterial contamination levels are high, then UVC technology alone may not be sufficient to achieve the desired level of effectiveness, researchers said. Sablani further remarked that research is underway to increase the effectiveness of UVC light on fruits with rough surfaces. The study was published in the International Journal of Food Microbiology. (full article at food.ndtv.com)

UV-C light is found to be effective in disinfecting food commodities without producing any chemical residue. However, the taste of the food changes to a certain extent after processing. The duration of exposure has to be right.

The disinfection cycle length depends on the nature of the surface being disinfected. UVC lamps that are for home use, are normally of low dose, and require a longer duration of exposure to a given surface to effectively inactivate the virus.

UV light is not a new discovery and we have known about it for centuries. It has been used in hospitals for decades to disinfect surfaces in the operating rooms and other areas and also for disinfecting drinking water and contaminated air.

LED UVC cannot effectively reach under surfaces that are covered in dirt or grime. The best way to clean therefore seems to be a combination of mild chemical disinfectants along with UV C.

Though UVC light may be harmful for humans, if used properly it is absolutely safe - it can be ensured that pathogens are killed, but no damage is caused to the surfaces.

Researchers are working on “far UVC light”, which is less harmful for humans and could still be used to eliminate microbes including the novel coronavirus. It could be used in permanent fixtures in public places to minimize the spread of viruses and other microbes. 

Though research shows that it can be and is being actually used by many restaurants for sweets and food packets most people would be apprehensive about using UVC lamps to disinfect food at their homes. As of now we have very limited published data regarding the wavelength, dose and duration of exposure of UVC radiation required to inactivate the SARS-CoV-2 virus but perhaps with time UVC will be used in homes for disinfecting fruits and vegetables too! That will definitely make life easier and also change our approach to future pandemics.

“We are in this together and we will get through this together.”

- UN Secretary-General Antonio Guterres

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