Impact of ultraviolet C treatment on sensory characteristics, amino acid profile, riboflavin content and toxicological activity of native whey

In the fight against fermentation-disrupting bacteriophages, UV-C irradiation is promising due to its capability of damaging nucleic acids and preventing organisms to replicate. The purpose of this study is to investigate the effect of this radiation on whey using three different devices (lab-/technical-scale, batch/continuous) and UV-C doses between 0.4 and 100 J mL−1. In vitro toxicity assays (Comet, WST-1, Ames) proved that irradiated whey does not exhibit any genotoxic, cytotoxic, or mutagenic activity and is presumed to be harmless to health. However, the irradiated product had an intense "cowish/stable-like/manure-like" off-flavor, which was identified as para-cresol by GC-MS-O. Riboflavin decay was observed as well as decreases in cystine and aromatic amino acids, whose degradation products are known to be odor-active. With our current data, we are not able to define a suitable process window or to recommend the application of this technology to treat whey.