Inactivation of E. coli and L. innocua in milk by a thin film UV-C reactor modified with flow guiding elements (FGE)

Sila Barut Gök^a, Eva Vetter^b, Lisa Kromm^b, Edgar Hansjosten^c, Andreas Hensel^c, Volker Gräf^b, Mario Stahl^b

Department of Food Technology, Çorlu Vocational School, Tekirdağ Namık Kemal University, Tekirdağ 59830, Turkey.

Abstract

In this study the suitability of a thin-film reactor (TFR) equipped with special flow guiding elements (FGE) was examined to analyse its capability to inactivate microorganisms in milk. Experiments were carried out with UHT-milk inoculated with Escherichia coli (E. coli), DH5α and Listeria innocua (L. innocua) WS 2258. Furthermore, the inactivation of microorganisms originally occurring in raw milk was investigated. E. coli, DH5α and L. innocua serving as biodosimeter were reduced by 4.58-log and 3.19-log, respectively. In milk, the original microorganisms showed a 4-log reduction. Without FGE the reduction was below 0.13-log. Thus, it can be derived that the efficacy of a UV-C thin-film reactor processing absorptive media like milk can be highly improved using FGE.

Keywords: UV-C, Ultraviolet, Milk, Thin film reactor, Escherichia coli, Listeria innocua.