Decontamination of dried whole black peppercorns using ultraviolet-c irradiation

Food Microbiol. 2020 Jun;88:103401. doi: 10.1016/ Epub 2019 Dec 13.


This study determined the efficacy of UV-C as a decontamination process against some foodborne bacteria in dried whole black peppercorns. Artificially-inoculated Salmonella enterica, Escherichia coli O157:H7, Listeria monocytogenes, Pseudomonas aeruginosa, and Staphylococcus aureus were subjected to UV-C with a surface irradiance of 0.43 mW/cm2 and were all found to exhibit a biphasic inactivation pattern with fast log-linear inactivation followed by a tail. Total log reductions (TLR) ranged from 1.92 (S. aureus) to 3.60 log CFU/g (E. coli O157:H7). Increasing the lamp number from 1 to 5 also linearly (R2 = 0.98) increased the surface irradiance from 0.43 to 1.70 and the TLR of the most resistant S. aureus from 1.92 to 2.62 log CFU/g. Quality evaluation showed very small, variable changes in color coordinates, which were not detected by a same/different test involving a 50-member sensory evaluation panel. Mercury deposition was not detected after a maximum exposure time of 90 min to 0.43 and 1.70 mW/cm2. Finally small, non-significant changes in the innate bacterial microflora of the black peppercorns were determined after 90 min-treatment using 1 lamp and 5 lamps, emphasizing the limitation of utility of UV-C as additional decontamination process for post-process-introduced microorganisms. Good Manufacturing Practices throughout the dried black peppercorn manufacturing process were recommended.

Keywords: Black peppercorns; Foodborne bacteria; UV-C irradiation.

MeSH terms

  • Bacteria / radiation effects*
  • Colony Count, Microbial
  • Colorimetry
  • Decontamination / methods*
  • Escherichia coli O157 / radiation effects
  • Food Irradiation / methods*
  • Food Microbiology / methods
  • Listeria monocytogenes / radiation effects
  • Microbial Viability / radiation effects*
  • Staphylococcus aureus / radiation effects
  • Ultraviolet Rays*