INHIBITION OF BACILLUS-CEREUS SPORES AND VEGETATIVE CELLS BY FATTY-ACIDS AND GLYCERYL MONODODECANOATE

Fatty acids and glyceryl monododecanoate (monolaurin) inhibited cell growth from Bacillus cereus spores and vegetative cells. The inhibitory activity decreased according to: stearic < oleic < linoleic < lauric < monolaurin < linolenic. Vegetative cells were similarly affected by monolaurin, oleic and Linolenic acids but were less sensitive to linoleic or lauric acids than their spores. Lauric acid (0.075 to 0.5 mM) inhibited cell multiplication, oleic acid (0.885 to 1.060mM) affected solely spore germination, whereas monolaurin (0.073 to 0.109 mM), linoleic (0.178 to 0.321 mM) and linolenic acids (0.036 to 0.054 mM) inhibited both spore germination and outgrowth. The effects of stearic and oleic acids were reversible whereas linoleic (0.885 to 1.065 mM) totally and irreversibly inactivated spores. Other inhibitors partially affected spores and vegetative cells. Starch neutralized the inhibitory activity of fatty acids except for Lauric acid at 1 mM and oleic acid. Starch antagonism decreased as fatty acid concentration increased.