Effects of mastic resin and its essential oil on the growth of proteolytic Clostridium botulinum
Daphne Phillips Daifasa, James P. Smit, a, Burke Blanchfieldb, Greg Sandersb, John W. Austinb and John Koukoutisisc
a Department of Food Science and Agricultural Chemistry, McGill University, Macdonald Campus, 21,111 Lakeshore Road, St. Anne de Bellevue, Quebec, Canada H9X 3V9
b Bureau of Microbial Hazards, Food Directorate, Health Products and Food Branch, Health Canada, Ottawa, Ontario, Canada K1A 0L2
c Collège d'Alfred, Université de Guelph, 31, rue St-Paul, C.P. 580, Alfred, Ontario, Canada K0B 1A0
Studies were done to determine the effect of mastic resin and its essential oil, alone and in conjunction with ethanol, on the growth of proteolytic strains of Clostridium botulinum in media, and on neurotoxin production in challenge studies with English-style crumpets. Preliminary studies, using a spot-on-the-lawn method, indicated that high levels of mastic resin in ethanol (~8% w/w) were required for complete inhibition of all strains of C. botulinum tested, but mastic resin in ethanol had a greater anti-botulinal effect than ethanol alone. However, only low levels of mastic oil (~0.3% v/v) were required for inhibition of proteolytic strains of C. botulinum. Both studies showed a strain specific inhibition, with C. botulinum type A strains being more sensitive to mastic resin and its essential oil than type B strains. However, mastic resin in ethanol proved to be more effective when used as a vapor phase inhibitor applied to cotton pads and placed inside inoculated plates than when added directly to media. While both mastic resin and its essential oil inhibited the growth of proteolytic strains of C. botulinum in vitro, they failed to inhibit neurotoxin production in challenge studies with C. botulinum in English-style crumpets.
Author Keywords: Mastic; Ethanol; Clostridium botulinum; Botulinum neurotoxin