Applications of light emitting diodes and their mechanism for food preservation

Abstract

In the food sector, light emitting diodes (LEDs) have a wide range of uses, including improving food production, extending the shelf life of perishables, and—most importantly—improving food safety. LEDs are semiconductor devices that, depending on the kind of conductors they are built of, emit light by electroluminescence across a range of wavelength spectrums. Compared to conventional light sources (ultraviolet [UV] light), LEDs are more energy‐efficient, eco‐friendly and have a lesser environmental impact. Moreover, LEDs have relatively lower warm up time and heat emissions, higher life expectancy and no mercury deposits compared to UV light. This article provides a comprehensive review of the food safety applications of LED showcasing its potential in microbial inactivation of clear, liquid food products as a potential alternative to traditional UV‐light technology. Optical properties (cloudiness, penetration depth of light) of the foods and geometrical design of the LED treatment chamber (distance from light source and intensity, wavelength of the light) play a key role in maximizing LED's efficacy for microbial inactivation. Additionally, a combination of wavelengths and photosensitizing compounds have proven to be synergistic in the application of this technology. There is a need for further research on the effect of LEDs on the safety and quality attributes of food and beverage products to continue with the feasibility assessment required to determine its potential at industrial scale.

Effect of Optimized UV-LED Technology on Modeling, Inactivation Kinetics and Microbiological Safety in Tomato Juice

“…However, Bintsis et al [14] reported that UV rays have a higher bactericidal potency depending on the type of liquid food. In addition, it has been thoroughly evaluated that not only is wavelength one of the critical factors but also others such as type of microorganism, impact on quality, inactivation mechanism, fluence and energy density [24]. In other words, to analyze an efficient UV-LED process on the inactivation of pathogenic bacteria, we must consider the above.…”

“…On the basis of the above, Cadet et al [23] and Ramesh et al [24] described that another mechanism of DNA destruction in microorganisms occurs when UV irradiation generates Reactive Oxygen Species (ROS). Photosensitizers are substances naturally present in the microbial cell and are stimulated to a higher energy level state.…”

Nanoporous Organic Frameworks as Light-Emitting Diodes: A Review

“…These include organic molecules for organic light-emitting diodes (OLEDs), − quantum dots (QDs) for quantum-dot light-emitting diodes (QLEDs), , perovskites, carbon nanotubes, biomass-derived materials, metal nanoclusters, porous materials, and so on. While LEDs are mainly used for displays in our everyday lives, their applications have also been extended to other functions such as data communications, biomedicine, and food preservation …”

Blue 405 nm LED light effectively inactivates bacterial pathogens on substrates and packaging materials used in food processing

“…However, limitations such as the low efficiency of the light sources, particularly at refrigeration temperatures 19 , a lack of systems that offer three-dimensional exposure of complex and large objects 20 , as well as the detrimental effects of direct UV exposure to mammalian cells, restrict the use of these technologies 17 , 21 . Light emitting diodes (LEDs) emitting electromagnetic radiation in the visible wavelengths have garnered increasing attention in recent years as a safe 22 , 23 , energy efficient 24 , 25 , non-UV-based microbial decontamination technology in the food industry 26 and clinical environments 27 , 28 . LED lighting is also increasingly used in horticulture, to increase plant photosynthesis and phototropism, or to extend the shelf life of fresh produce in the postharvest stage 24 .…”

“…Light emitting diodes (LEDs) emitting electromagnetic radiation in the visible wavelengths have garnered increasing attention in recent years as a safe 22 , 23 , energy efficient 24 , 25 , non-UV-based microbial decontamination technology in the food industry 26 and clinical environments 27 , 28 . LED lighting is also increasingly used in horticulture, to increase plant photosynthesis and phototropism, or to extend the shelf life of fresh produce in the postharvest stage 24 . For example, colored LED lights were reported to delay the ripening in tomatoes and broccoli through retarding the chlorophyll degradation and slowing down sugar loss, thus extending their shelflife 29 – 31 .…”