ades ▁past , ▁also ▁demonstrate ▁b acter ic idal ▁eff ica cies , ▁but ▁within ▁a ▁somewhat ▁longer ▁time ▁frame ▁than ▁pure ▁co pper . ▁All ▁nine ▁br ass es ▁tested ▁were ▁almost ▁completely ▁b acter ic idal ▁( over ▁ 9 9 . 9 % ▁kill ▁rate ) ▁at ▁ 2 0   ° C ▁within ▁ 6 0 – 2 7 0 ▁minutes . ▁Many ▁br ass es ▁were ▁almost ▁completely ▁b acter ic idal ▁at ▁ 4   ° C ▁within ▁ 1 8 0 – 3 6 0 ▁minutes . ▁ ▁The ▁rate ▁of ▁total ▁micro b ial ▁death ▁on ▁four ▁bron zes ▁varied ▁from ▁within ▁ 5 0 – 2 7 0 ▁minutes ▁at ▁ 2 0   ° C , ▁and ▁from ▁ 1 8 0 ▁to ▁ 2 7 0 ▁minutes ▁at ▁ 4   ° C . ▁ ▁The ▁kill ▁rate ▁of ▁E . ▁col i ▁O 1 5 7 ▁on ▁co pper - nick el ▁allo ys ▁increased ▁with ▁increasing ▁co pper ▁content . ▁Zero ▁b acter ial ▁counts ▁at ▁room ▁temperature ▁were ▁achieved ▁after ▁ 1 0 5 – 3 6 0 ▁minutes ▁for ▁five ▁of ▁the ▁six ▁allo ys . ▁Despite ▁not ▁ach ieving ▁a ▁complete ▁kill , ▁al loy ▁C 7 1 5 0 0 ▁achieved ▁a ▁ 4 - log ▁drop ▁within ▁the ▁six - hour ▁test , ▁representing ▁a ▁ 9 9 . 9 9 % ▁reduction ▁in ▁the ▁number ▁of ▁live ▁organ isms . ▁ ▁E ffic acy