# UV Light Application as a Mean for Disinfection Applied in the Dairy Industry
## 1 Introduction  
Foodborne illnesses induced by the ingestion of etiological agents make food safety a critical problem for the food industry and food services. According to the World Health Organization, 600 million people-almost one out of every ten people on the planet-become sick after consuming contaminated food each year, with 420,000 of them dying [1]. Pasteurization and ultra-high temperature (UHT) treatments are two thermal processes commonly used in dairy production. Heat treatments may have a detrimental impact on food by altering sensory properties including color, texture, and taste. Furthermore, the consequence may be a reduction in nutritive value, for instance, the loss of certain bioactive compounds, enzymatic breakdown, vitamin loss, lipid rancidity, and denaturation of proteins, which may result in low food quality. For instance, as the temperature rises, the level of the milk serum component changes. The levels of calcium and phosphate in milk serum drop from the initial level 9 to 3 mmol L\({}^{-1}\) and 12 to 8 mmol L\({}^{-1}\), respectively, as the temperature rises from 4 to 90 \({}^{\circ}\)C; heat-induced reductions in serum magnesium and citrate are also found, but to a lesser extent [2]. There is no change in the level of potassium and sodium in the milk serum caused by heat treatment [3]. The pH of milk decreases as it is heated, and at temperatures above 80 \({}^{\circ}\)C, the pH decreases linearly with increasing temperature [4, 5]. However, the heat treatment of milk which occurs at temperatures above 70 \({}^{\circ}\)C will change the properties of milk fat globule membrane (MFGM) proteins, leadingto the exposure of reactive groups. Additionally, more extreme heat treatments (above 90 \({}^{\circ}\)C) can cause permanent changes in mineral balance in milk [6]. Another drawback is that thermal processing consumes a lot of energy, which can lower the final product value and reduce industry profitability [1]. At a compound annual growth rate (CAGR) of 6.9%, the global market of dairy product is projected to rise from $675.78 billion in 2020 to $722.14 billion in 2021 and at a CAGR of 7%, the market is forecast to hit $956.26 billion in 2025 [7]. As a result, new manufacturing methods must be developed to satisfy global demand. In European Union, a food product should be considered a novel food when it is produced with a process not used within the Union before 15 May 1997, and which results in significant changes in the composition or structure of food affecting its nutritional value, metabolism or level of undesirable substances [8]. Non-thermal technologies, i.e., microfiltration, UV light processing, pulsed light, high hydrostatic pressure, high-pressure homogenization, pulsed electric fields, ohmic and microwave heating, and carbon dioxide processing, have recently been implemented as an alternative to thermal treatment and have piqued public interest as a means of avoiding nutrient damage that would otherwise occur during food heat processing [9]. The Sun is the primary source of Ultraviolet light, which radiates light at several different wavelengths [10]. The alternative UV radiations can be emitted from taming beds, mercury vapor lamps, selected halogens, fluorescents, incandescent lights, and some types of lasers [11]. Ultraviolet radiation is a non-ionizing source of invisible light that exists between visible light and X-rays in the electromagnetic spectrum (EM). UVA (315-400 nm), UVB (280-315 nm), UVC (200-280 nm), and vacuum-UV (100-200 nm) are the four major forms of UV rays produced by ultraviolet light with wavelengths between 100 and 400 nm as shown in Figure 1[1, 12]. UV has the best germicidal effect when the wavelength is about 254 nm, which mercury vapor lamps emit [13]. The microbial deactivation can become more efficient through greater penetration of UV light which is possible with the correct UV source [10].