Each of the tested microbial strain was propagated and regularly maintained so that the cells were of similar culture age when subjected to the UV-C inactivation studies. Briefly, a loopful of cells was obtained from refrigerated stock cultures and activated in 10 ml sterile nutrient broth (NB, HiMedia) tubes; and incubated at 35 °C for 18 h. Cells from the activated cultures were further enriched in another 10 ml NB at 35 °C for 18 h. A loopful of cells was obtained from each of the enriched cultures and thereafter streaked onto NA slant prior to incubation at 35 °C for 18 h. The tubes were then stored at 4 °C. Each of the cultures was propagated and subjected to the previously described activation-enrichment-storage cycle every 14 d.