Lab M, specialist microbiology culture media manufacturer, has introduced new variants of Fraser Broth - known as Fraser BrothPLUS - for the enrichment of Listeria species. The new products are designed to help overcome issues with conventional formulations when culturing organisms for subsequent ELISA analysis and they provide 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 ½ Fraser BrothPLUS and Fraser BrothPLUS, the antibiotic supplement is blended into the base medium, but the ferric ammonium citrate (FAC) component is supplied separately as a supplement. By separating the FAC from the base 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 ½ strength supplement, it can also be used as a primary resuscitation or enrichment medium.