EFFECT OF ULTRAVIOLET (UV-C) LIGHT AND GASEOUS OZONE ON MICROBIAL AND COLOR QUALITIES OF WHOLE BLACK PEPPER SEEDS (PIPER NIGRUM L.)

Microbial contamination of spices, especially black pepper, may sometimes reach as high as 8 log cfu/g, which can cause a major problem in the quality and safety of foods they are added. This study aimed to explore the potential of ultraviolet C (UV-C) light and ozone for decontamination of black pepper seeds.Ozone (15 ppm for 1 h) and UV-C (28.8 J/cm²) treatments were applied alone, in succession, or simultaneously to whole black pepper seed with a laboratory scale fluidized bed UV-C system. Total aerobic mesophilic bacteria (TAMB) count (in uninoculated seeds), Escherichia coli (E. coli) count (in inoculated seeds) and color (L*, a* and b*) of black pepper were evaluated.Ozone and UV-C treatments alone caused 0.41 and 0.77-log reduction in the initial TAMB count (6.97 log cfu/g), respectively. TAMB decreased by 0.74 and 0.66-log upon successive and simultaneous treatments, respectively. Thus, the combined treatments did not have any additive or synergistic effects on TAMB. Both ozone and UV-C treatments alone resulted a 0.8-log reduction in the initial E. coli count of 6.3-log. The combined treatments caused an additive effect on inactivation of E. coli in black pepper seeds. The successive and simultaneous treatments caused 1.7 and 1.4-log reductions in the E. coli, respectively. None of the treatments affected the color (L*, a* and b* values) significantly.