A Less Hazardous Enrichment Broth for Listeria without Cycloheximide and Acriflavine

Abstract

The hazardous substances cycloheximide and acriflavine are used as selective agents in standard listeria enrichment broths. This study was undertaken to develop a less hazardous listeria enrichment broth in order to avoid occupational-safety and waste-management problems. The replacement of cycloheximide (50 mg/l) and acriflavine (15 mg/l) with natamycin (25 mg/l), moxalactam (10 mg/l) and bacitracin (20 mg/l) did not inhibit the growth of Listeria monocytogenes. Furthermore, most of the competing microbial strains were suppressed equally well or better in this less hazardous modification than in a standard broth.