Antibacterial Effects of Garlic Extract on Vibrio parahaemolyticus in Fish Meat

The aqueous extract of garlic (Allium sativum L.) was prepared from homogenate of fresh garlic bulbs blended with an equal weight of water. This mixture was then sterilized by filtration. The antibacterial effects of garlic extract on Vibrio parahaemolyticus was studied by using heart infusion broth containing 3% NaCl (Hl broth) and two kinds of fish meat homogenate. We found that garlic extract had a strong growth inhibitory activity against V. parahaemolyticus in both the Hl broth and fish meat homogenate.When Hl broth containing 2.5% garlic extract was used as the growth media, no bacterial growth of V. parahaemolyticus was observed during one day's incubation. The addition of 5% garlic extract to horse mackerel meat homogenate caused a 93% decrease in the 105 inocula of tested bacteria. In the bonito meat homogenate, 5% garlic extract only slightly inhibited growth while 10% garlic extract resulted in an 85% decrease in the 104 inocula of tested bacteria. Experiments using autoclaved raw fish meat of the above-mentioned two species gave almost the same results.The antibacterial activity of garlic extract was stable on storage at 4°C for 5 days, but decreased on storage at 25°C for 2 days.