Concentration dependence of NaHAc2 kill rate.
To elucidate the concentration dependency of the
antimicrobial effect of NaHAc2, static 24-h-old bio-
films grown in microtiter plates were treated for
another 24 h with increasing amounts of NaHAc2, as
depicted in Table 2, with the decrease in pH, as seen
in Table 2. The antimicrobial effect was determined
by plating the treated and nontreated biofilms. To
ensure complete removal of all the adhering bacteria,
the wells of the microtiter plate were washed
mechanically. We observed a complete killing effect
of the biofilm using 1.75% (w/v) added NaHAc2 and
higher. Surprisingly, we did not observe the strict
pH-dependent killing for NaHAc2, which we had
previously observed using acetic acid