Objective: To determine the disinfecting properties of benzalkonium ch
loride as an irrigation agent. Design: Comparison was made between irr
igation of contaminated muscle strips with benzalkonium chloride and n
ormal saline (control). Summary of Background Data: Benzalkonium chlor
ide is a cationic disinfectant. which has questionable able efficacy i
n an organic environment. However, no previous study has attempted to
use high volumes of this cationic solution to overcome the neutralizin
g effect of organic tissue and thus maintain this-detergent's germicid
al properties. Methods: 2.5cm x 0.5cm x 0.5cm pieces of bovine muscle
were aseptically cut from the center of freshly harvested beef muscle
and incubated with 1.0 x 10(7) colony form in units of bacteria for 15
minutes. The muscle strips were then irrigated with either 100mL, 1L,
or 10L of benzalkonium chloride at a 1:2000 concentration in normal s
aline. Normal saline was used as the control. The muscle strips were s
onicated to remove adherent bacteria; the number of living organisms w
as determined by quantitatively culturing the sonicate. Results: In vi
tro, benzalkonium chloride was superior to normal saline at disinfecti
ng bovine muscle (p less than or equal to 0.001). When 10L of benzalko
nium chloride irrigation was used, no living bacteria could be recover
ed (p less than or equal to 0.012). Conclusion: In this experimental s
etting benzalkonium chloride was an effective disinfection agent, with
enhanced activity at large volumes.