ANTIMICROBIAL SPECTRUM AND TARGET SITE OF D-3-PHENYLLACTIC ACID

Geotrichum candidum excretes D-3-phenyllactic acid, which inhibits the growth of Listeria monocytogenes. It was found to inhibit a range of Gram-positive bacteria found in humans and foodstuffs, such as Staphyl ococcus aureus and Enterococcuss faecalis, acid Gram-negative bacteria from humans, such as Providencia stuartii and Klebsiella oxytoca. Sca nning electron microscope studies on the effect of D-3-phenyllactic ac id on L. monocytogenes showed that it caused changes in bacterial beha vior and structure. The bacteria formed aggregates acid secreted polys accharides; their cell walls lost their rigidity, causing the cells to swell. Finally the bacteria broke down completely and the cells disin tegrate. (C) 1998 Elsevier Science B.V.