Thirteen popular Thai condiments were screened for
inhibitory activity against the pandemic strain of
V. parahaemolyticus PSU 335. Freshly squeezed extracts
of three condiments, galangal, garlic and lemon showed
inhibitory activity with a diameter of the clear zone
of 13.670.5, 11.670.5 and 8.671.2 mm, respectively
(Table 1). Suppression of growth of V. parahaemolyticus
by galangal, garlic and lemon was confirmed using the
pandemic strain of V. parahaemolyticus PSU 414 and nonpandemic
strains PSU 253 and PSU 1702. It was found
that garlic was the most effective herb that inhibited
V. parahaemolyticus (Po0.001), and galangal was superior
to lemon (Po0.001) (Table 2). Although the two nonpandemic
strains (PSU 253 and PSU 1702) showed less
inhibitory effect by garlic and lemon, respectively, the
average mean of these two strains was not significantly
different from those of the pandemic strains (PSU 335 and
PSU 414) (P40.05).
Most of the popular Thai spicy soups use seafood for
cooking, and contain galangal. Therefore, this herb was
extracted by chloroform, methanol and water and the