Far infrared and ultraviolet radiation as a combined method for surface pasteurization of black pepper seeds

This study presented the potential of far infrared (FIR) and ultraviolet (UVC) radiation for surface pasteurization of black pepper seeds. FIR treatment at different exposure times and temperatures was applied followed by constant UVC treatment with an intensity of 10.5 mW/cm² for 2 h. Then, the reduction on total mesophilic aerobic bacteria (TMAB) and mold-yeast contents were determined, and quality changes of the seeds were evaluated. TMAB of the seeds decreased to the target level of 10⁴ CFU/g after 4.7 and 3.5 min FIR treatment at 300 and 350 °C, respectively. Under given conditions, complete elimination for other microorganisms (TMY, Escherichia coli and Bacillus cereus) was also obtained while there were no significant changes in volatile oil and color. UVC however, alone or in combination with FIR, did not exhibit a significant reduction in TMAB content. Consequently, FIR treatment was suggested to be a promising method for the surface pasteurization of black pepper seeds.