# UV Light Application as a Mean for Disinfection Applied in the Dairy Industry
## 4 Effects of UV on Food Components and Quality
The potential effect of UV-C and pasteurization on the properties of milk and dairy products are shown in Table 3.  
In general, UV light treatment of food has been shown to have no negative consequences, particularly when applied in moderate quantities [71]. However, for certain foods, alteration and optimization of the UV radiation can be needed for the effective application of the procedure [44]. In the case of the FFA profile, some studies [62] showed a significant increase in %FFA after combined use of HTST pasteurization and UV light treatment. However, it was concluded that it may result from the possible damage to MFGM, which enhanced oxidative rancidity, due to excessive pumping of the milk. \begin{table}
\begin{tabular}{c c c} \hline \hline
**Quality Parameter** & **Pasteurization** & **UV-C** \\ \hline Protein denaturation & Increases with temperature [60] & Little [61] or no [51] effect \\ \hline Protein oxidation & No difference [62] & Little effect when treated with less than \\ \hline Protein precipitation & No effect & Observed [59] \\ \hline Fatty acid profiles & \begin{tabular}{c} HTST treatment: almost no effect, UHT \\ treatment: Considerable changes [64] \\ especially decrease in PUFA content and \\ increase in saturated FA, including low \\ molecular FA \\ \end{tabular} & Almost no change [65; 66] \\ \hline Lipid oxidation & \begin{tabular}{c} Little [62] or significant changes [67]; \\ temperature-dependent \\ \end{tabular} & No changes [52] \\ \hline Level of vitamin D3 & No impact [68] & Increases [65] \\ \hline Level of vitamin B12 & Reduces [62] & No impact [62] \\ \hline Thiobarbituric acid reactive substances & No significant difference [62] & Significant [66] or no [62] change \\ \hline Level of aldehydes and hydrocarbons & Increases [69] & Increases [61] \\ \hline pH & Decreases [62] & Mild or no impact [1; 59; 61] \\ \hline Sensory characteristics & Decrease as temperature increases [70] & Dose-dependent [61; 66] \\ \hline Color & \
\begin{tabular}{c} Changes more likely at a higher intensity \\ (95 \({}^{\circ}\)C and 45 s) [64] \\ \end{tabular} &
\begin{tabular}{c} Unchanged [56; 59] or significant changes \\ \end{tabular} \\ \hline \hline \end{tabular}
\end{table} 
Table 3: An overview of the effects of UV-C radiation and pasteurization on the components, physicochemical parameters, and sensory attributes of milk and dairy products. In consideration of UV impact on sensory characteristics, which are very important factors determining consumer acceptance of food products, it must be stated that different findings were reported. In general, the dose of UV radiation to a great extent influences the degree of changes in sensory properties. For instance, [PERSON] et al. [61] reported differences in odor and flavor in Gouda and Manchego cheeses immediately after treatment with doses of \(\geq\)4.2 J/cm\({}^{2}\) as a result of sulfur notes increase. They have also demonstrated that the level of sulfur volatile compounds and the corresponding sensory notes disappeared during cold storage. The study of [PERSON] et al. [66] showed that ultraviolet irradiation at the wavelength 254 nm and a dose of 15.8 \(\pm\) 1.6 mJ/cm\({}^{2}\) resulted in changes in the chemical and sensory properties of fluid goat milk. Whereas, [PERSON] et al. [65] showed no effect on fatty acid profile during UV treatment of milk either raw or pasteurized for 5-25 min which corresponded to the surface bactericidal irradiation dose 5.1-102 mJ/cm\({}^{2}\). The sensory defects that were reported after UV treatment was described as follows: tallowy flavor [62], manure, stinky, barnyard, and goaty aroma [66], burnt, off, strong and stale [72], burnt feather [51], and burned flavor [53].