Antimicrobial Activity of the Essential Oil of Mastic Gum (Pistacia lentiscus var. chia) on Gram Positive and Gram Negative Bacteria in Broth and in Model Food System
Chrysoula C. Tassoua, * and G. J. E. Nychasb
a National Agricultural Research Foundation, Institute of Technology of Agricultural Products, S. Venizelou 1, Lycovrisi 14123 Athens Greece
b Agricultural University of Athens, Department of Science of Food and Agricultural Industries, Laboratory of Food Microbiology and Biotechnology, Iera Odos 75 Athens 11855 Greece
The addition of mastic gum in broth culture inoculated with Staphylococcus aureus, Lactobacillus plantarum, Pseudomonas fragi and Salmonella enteritidis inhibited the growth of these organisms as monitored with the Malthus Instrument (in microsiemens). The rate of inhibition was greater on Gram positive bacteria than that observed on Gram negative bacteria. In most cases the size of inoculum and the concentration of mastic gum affected the growth/survival of the organisms. The addition of EDTA in coliform broth increased the inhibitory activity of mastic gum against Salmonella enteritidis, but did not affect significantly the inhibition of this organism in Model Food System (skim milk) at 37°C.