28 June 2006

New variants of Fraser Broth – known as Fraser Broth^PLUS – have been introduced to overcome issues with conventional formulations when culturing all Listeria species for subsequent ELISA analysis. Specialised peptones, together with the blending of the antibiotic supplement into the basal medium significantly improves isolation of target organisms. This not only benefits those using ELISA-based methodology, but also the more classical use of Fraser Broth as an additional supplement of ferric ammonium citrate is also available. Lab M's new Fraser Broth^PLUS provides users with a valuable choice.

The presence of antagonistic compounds in conventional formulations appears to interfere with subsequent ELISA procedures by compromising the isolation rates of target organisms. With Lab M’s new Half Fraser Broth^PLUS and Fraser Broth^PLUS, the antibiotic supplement is blended into the basal medium, but the ferric ammonium citrate (FAC) component is supplied separately as a supplement. By separating the FAC from the basal medium, it can be omitted for improved ELISA performance, or included for compliance with the ISO 11290 standard. 

Fraser Broth is traditionally used as a secondary enrichment medium for the isolation of all Listeria species. With the incorporation of half-strength supplement, it can also be used as a primary resuscitation or enrichment medium.