For UV-C challenge studies, 0.04 ml of the acclimatized cell suspension was pipetted to 3.96 ml filter-sterilized coconut liquid endosperm in a sterile 35 by 10 mm petri dish to introduce an initial population of approximately 6.0 log CFU/ml. The inoculated liquid endosperm (7 mm thick in the petri dish) was exposed to UV-C at different time intervals between 0 and 30 s, while simultaneously being stirred to allow even exposure to radiation. A fabricated box, with 15 W UV-C lamp (Sankyo Denki, Japan) that predominantly emits 253.7 nm, with a lamp to sample surface distance of 14 cm, was used in UV-C inactivation studies. To confirm the dominant radiation emitted by the UV-C lamp in the fabricated box, the source was subjected to optical emission spectroscopy at the same treatment distance of 14 cm (Fig. 1b). Emission measurement was conducted using a spectrometer (Ocean Optics, Inc. FL., USA) with a dispersion of 0.25 nm per pixel, and an optical resolution of 1.09 nm in the range of 200–1100 nm.