Title : Effect of UV-C and steam treatment on microbial decontamination of chilli powder (Capsicum annuum L.)
Abstract:
There is a growing need to develop novel decontamination technologies for spices, as existing methods often have limitations, particularly in terms of their impact on sensory quality. Therefore, exploring and comparing different decontamination approaches is essential to generate reliable data that can support the spice industry in selecting the most suitable and effective technologies. The present study compares UV-C and steam treatment decontamination of naturally contaminated chilli powder. Naturally contaminated chilli powder samples (aw 0.6-0.7) were treated with UV-C radiation (254 nm, 10-30 min) and saturated steam (98-120°C, 2-5 min). Post-treatment results included microbial analysis (total plate count, yeasts/molds, spores via pour-plate method), colorimetry (Lab* values, ΔE), moisture content and water activity.
Steam treatment can achieve significant microbial reductions (>4 log CFU/g for total counts) while largely preserving bioactive compounds. In contrast, UV radiation provides a non-thermal, surface-level decontamination approach with moderate reductions (approximately 1–3 log), but its effectiveness in powdered samples is limited by shadowing effects and requires careful dose optimization to prevent quality deterioration, such as pigment degradation. The overall results demonstrate that both the treatments were effective in the reduction of microbial content but the quality attributes were more stable in steam treatment as compare to UV -C therefore the steaming method was chosen a viable technology for reducing the microbial content in chilli powder.
