Evaluation of UV‐C LEDs efficacy for microbial inactivation in tender coconut water

Abstract

Consumer preference toward healthy refreshing and rehydrating drinks from carbonated drinks has shifted the positioning of coconut water from other fruit juices due to its low acid and sugar content (Tan et al., 2015). While thermal processing is an effective method for microbial safety, the heat treatment of coconut water caused rancidity and loss of nutritional quality (Fan, 2002).The application of UV-C is one of the established non-thermal technologies for processing juices and foods which limits the loss of organoleptic properties. UV-C has been proven for its germicidal effect on foodborne microbes (Koutchma, 2008) with no known undesirable by-products of public health concern. UV-C irradiation does not lead to the production of chemical residues that could alter the organoleptic characteristics of the product (Yannam et al., 2020).The ultraviolet germicidal irradiation on microorganisms causes DNA damage resulting in the formation of pyrimidine dimers, hence making the microorganisms unable to reproduce effectively (Chatterley & Linden, 2010;Malik et al., 2017). It is well noted that DNA absorbs maximum wavelength at 260 nm (Malik et al., 2017), but the optimum wavelength can be greatly varied between the species of microorganisms, growth media, the density of the microbial population (Chang et al., 1985;Wright et al., 2000), and other distinctive properties like composition and type of food.The majority of studies were performed with UV-C mercury lamps but mercury lamps pose lamp breakage and mercury leak, required warm-up time for necessity action (Chatterley & Linden, 2010), and periodic replacements of lamps because of short life cycles. Unfortunately, UV mercury lamps cannot be manufactured at various peak emission wavelengths other than 253.7 nm

Applications of light emitting diodes and their mechanism for food preservation

“…This group of researchers also showed greater inactivation in PBS compared to NB demonstrating the protective effects of solids and other organic matter. Maguluri et al (2021) demonstrated a significant reduction of 6.2 log 10 CFU/ml of E. coli (ATCC 8739) in tender coconut water (TCW), with an application of UV at a dose of 28 mJ/cm 2 . In addition the authors demonstrated a 6.3 and 5.6 log 10 CFU/ml reduction of Salmonella enterica (ATCC 13314) and L. monocytogenes (ATCC 19111), respectively, with a dose application of 21 mJ/cm 2 .…”

Dynamic Thermal Treatments in Green Coconut Water Induce Dynamic Stress Adaptation of Listeria innocua That Increases Its Thermal Resistance

“…While non-thermal methods have proven effective in reducing bacterial pathogens in coconut water [13,[15][16][17], it is worth noting that these investigations were conducted on a small laboratory scale (volumes of 5-10 mL) and employed varying process parameters. Therefore, a direct comparison of their efficacy with the current study, which simulates industrial dynamic treatment conditions, is not feasible.…”

“…Different non-thermal decontamination techniques for coconut water have been investigated, including pulsed light [15], UV-C light [16], atmospheric cold plasma [17] and high hydrostatic pressure, among others [13]. These non-thermal treatments have shown different levels of effectiveness, but experience limitations for their commercial implementation, such as high costs and scaling-up [13].…”