Decontaminating with UV-C light? Here’s what you need to know
By Danny Bayliss, New Technologies Lead - 15 December
As businesses look for new ways to combat the virus that causes COVID-19, the
application of ultraviolet light has seen an incredible uptake. Ultraviolet (UV) light technologies have
been around for a long time, but only in the past few years has the food and drink industry really taken an
interest in it. As this technology grows in popularity, it’s important to build your understanding of how it
can be applied safely and how it can help you.
Before we delve any deeper, for those unfamiliar with UV light it’s worth covering
the basics. UV light is part of the electromagnetic spectrum and similar to the light we see with our eyes,
but with shorter wavelengths. There are three types: UV-A, B and C. It is the UV-C light that we use as a
germicide due to its specific wavelength’s (200 – 280 nm) effectiveness at inactivating microorganisms –
making it ideal for decontamination applications in the food industry.
How UV-C light helps the industry
UV-C light was first used to kill bacteria in 1873, and since then we’ve learnt of
its vast number of potential applications. Most notably, its germicidal qualities have been investigated and
exploited. The non-ionising light can inactivate viruses (including SARS-CoV-2 that causes COVID-19),
bacteria, yeast, moulds and spores. How? The UV-C light is absorbed by the microorganism’s DNA, changing the
genetic material’s structure and preventing it from replicating. As a result, the organism dies.
UV-C light can be used on a variety of food products to help:
- improve quality
- extend shelf-life, or
- reduce water and chemical usage while also reducing a product’s microbial level.
Its applications are diverse. For example, at Campden BRI we’ve used UV-C light to
treat a range of products and surfaces to validate them against pathogen inactivation. More recently we have
been exploring UV-C light for in-pack surface decontamination and nutrient boosting applications.
Using UV-C light for zonal transfer – what are the requirements?
The use of UV light to treat items being moved from a low risk area to a high care
or high risk area is growing in the food industry. This application, which decontaminates products so that
there is a reduced chance of pathogens entering these zones, is becoming common practice for some food
businesses. However, it’s important to note that manufacturers must have their UV light systems validated if
used for this purpose. Otherwise they may not be compliant with BRCGS Global Standard for Food Safety Issue
Section 8.1.3 of this standard states that, “Where physical barriers are not in
place, the site shall have undertaken a documented risk assessment of the potential for cross-contamination,
and effective, validated processes shall be in place to protect products from contamination.” While this
sounds straightforward, much of the data that exists in literature has been established with water and air.
For zonal transfer, the different surfaces and organisms of concern need to be tested to ensure the systems
are performing correctly. Need help with this? With extensive experience in UV-C light systems, our team at
Campden BRI can provide you with support in this area.
It’s also worth noting that - due to differences in their DNA, external structures,
pigments and repair mechanisms - different microorganisms have varying levels of susceptibility to UV light.
So, before validating your systems, you should first consider your target organisms so you know the correct
dosages to validate them against.
What are the limitations of this technology?
As it’s light-based, UV-C systems must be able to ‘see’ the organisms to inactivate
them. So it goes without saying that shadows and shields dramatically reduce this technology’s
effectiveness, as well as the structure of the surface you are treating. For example, perfectly smooth
plastic sheeting may be easy to treat, but if it’s crimpled beforehand then this will create tiny pockets of
cover and protection for the target organisms.
Need help with your UV light systems?
Our experts have in-depth knowledge of many new technologies used in the food
industry and are perfectly equipped and positioned to support you with your UV light needs. Whether this is
further guidance, advice or testing with UV-C systems, please get in touch – we’d love to help.
After finishing his PhD in cold plasma technology Danny joined Campden BRI where he has been in various new technology roles since 2012. Danny's main research interests have been in the field of emerging processing and preservation technologies for the food industry.