A QUANTITATIVE ASSESSMENT OF THE ANTIMICROBIAL ACTIVITY OF GARLIC (ALLIUM-SATIVUM)

An aqueous extract of freeze-dried garlic (Allium sativum), when incor porated into growth media, inhibited many representative bacteria, yea sts, fungi and a virus. All microorganisms tested were susceptible to garlic. Quantitative assessment of the minimum inhibitory concentratio ns for bacteria and yeasts showed values ranging from 0.8 to 40.0 mg g arlic ml-1. Fungal radial colony growth was inhibited by at least 25% at concentrations as low as 2.0 mg garlic ml-1. The 50% endpoint neutr alization titre for rotavirus was 2.4 to 2.8 mug ml-1. Lactic acid bac teria were the least sensitive microorganisms to the inhibitory effect s of garlic. In mixed culture studies of Lactobacillus acidophilus and Escherichia coli, garlic prevented the establishment of E. coli, alth ough the final outcome of competition was not affected.