Design and Development of a UV Reactor Integrated with a Microfiltration Module for Removal of Somatic Cells and Inactivation of Bacteria in Raw Milk
Athare Dnyaneshwar Kedarnath *
Department of Dairy Engineering, Dairy Science College, KVAFSU, Hebbal, Bengaluru, Karnataka, India.
Rajunaik B.
Department of Dairy Engineering, Dairy Science College, KVAFSU, Hebbal, Bengaluru, Karnataka, India.
Mahesh Kumar G.
Department of Dairy Engineering, Dairy Science College, KVAFSU, Hebbal, Bengaluru, Karnataka, India.
Ramachandra B.
Department of Dairy Microbiology, Dairy Science College, KVAFSU, Hebbal, Bengaluru, Karnataka, India.
Rajanna M
Department of Dairy Chemistry, Dairy Science College, KVAFSU, Hebbal, Bengaluru, Karnataka, India.
Devaraju R.
Department of Dairy Engineering, Dairy Science College, KVAFSU, Mahagaon Cross, Kalaburagi, Karnataka, India.
*Author to whom correspondence should be addressed.
Abstract
This study focuses on the design, development, and evaluation of a hybrid ultraviolet–microfiltration (UV–MF) module for improving the microbial quality of raw milk while maintaining its overall quality. The system was developed by integrating a 3 µm microfiltration unit with two custom-fabricated UV-C reactors arranged in series to overcome the limitations of low UV transmittance in milk. Reactor 1 was designed with a 28 W UV lamp and a 3.5 mm annular flow gap, while Reactor 2 incorporated a higher-power 62 W lamp with a reduced 2.0 mm flow gap to enhance UV exposure under continuous flow conditions. Both reactors were fabricated using food-grade stainless steel and quartz sleeves to ensure hygienic operation, leak-proof performance and ease of maintenance. The microfiltration stage acted as a critical pre-treatment by reducing turbidity and somatic cell load, thereby improving UV treatment efficiency. Limited performance evaluation indicated effective bacterial reduction, unchanged milk composition, delayed acidity development and acceptable sensory quality, demonstrating the suitability of the developed UV–MF system as a compact and non-thermal processing approach for dairy and food applications.
Keywords: Raw milk, Microfiltration, UV-C treatment, UV Reactor, Bacterial inactivation, Non-thermal processing