Determination of the utility of ultraviolet-C irradiation for dried bay leaves microbial decontamination through safety and quality evaluations

Abstract

This study was conducted to determine the efficacy of UV-C irradiation for safety and quality of dried bay leaves. Cocktails of microorganisms of the same species were prepared and inoculated onto the leaves, which were thereafter subjected to UV-C irradiation. Results showed that all tested organisms, which included Escherichia coli O157:H7, Salmonella enterica, Pseudomonas aeruginosa, Listeria monocytogenes, and Staphylococcus aureus, exhibited inactivation behaviors in the irradiated leaves that are characterized by initial log-linear population decline, followed by inactivation tail. The Total Log Reductions in the organisms after exposure to 3942 mJ/cm2 UV-C dose ranged from 2.70 to 3.93 log CFU/g. Furthermore, subjecting the bay leaves to UV-C of as much as 13662 mJ/cm2 did not significantly alter color, and visual sensory properties, and did not result in mercury deposition. Microbiological quality indicators of the bay leaves, including Total Plate Count and Yeast and Molds Count were improved by the UV-C irradiation. These results contribute in further understanding the scope and limitations of using UV-C as a decontamination technique for specific food product such as dried bay leaves.