Decontamination of powdery and granular foods using Continuous Wave UV radiation in a dynamic process

The purpose of this study was to investigate the potential of Continuous Wave UV radiation, applied in a dynamic process, to reduce Enterobacteriaceae counts in powdery and granular foods. Several food matrices were inoculated with a test strain (Escherichia coli LMG 8063) and radiated for 1 h with UV (254 nm, 2.88 mW/cm2). The particles were constantly homogenized under the UV source. Depending on the food matrix, reductions of 0.7-4.8 log cycles were obtained. For meringue chunks, a storage period of 20 h after inoculation prior to UV treatment caused a smaller reduction of the test strain (2.7 log cycles) than when radiation was applied immediately after inoculation (4.8 log cycles). Different initial contamination levels were tested. Higher inoculation levels tended to yield lower reductions. The results demonstrate that Continuous Wave UV radiation can be applied for microbial decontamination of specific powdery and granular food products under continuous homogenization.