Pilot scale study on UV-C inactivation of bacterial endospores and virus particles in whole milk: evaluation of system efficiency and product quality

Abstract

UV-C processing of whole milk (WM) using a designed pilot scale Dean flow system was conducted at flow rates (11.88, 23.77, and 47.55 gph), Reynolds number ranges from 2890-11562 and the Dean number (at curved region) calculated as (648-2595) to inactivate bacterial endospores and virus particles. Biodosimetry studies were conducted to quantify the reduction equivalent fluence at selected experimental conditions. Results revealed that the fluence distribution improved as flow rate increases, attributed to increase in Dean effects and turbulence intensity. Microbial inactivation studies conducted at 47.55 gph showed 0.91 {+/-} 0.15 and 2.14 {+/-} 0.19 log reduction/ pass for B. cereus endospores and T1UV phage. Linear inactivation trend was observed against number of passes which clearly demonstrates equivalent fluence delivery during each pass. Lipid peroxidation value and volatiles profile did not change significantly at UV fluence of 60 mJ/cm2. Lower EEO value signifies the higher electrical efficiency of the system.