Description
General description
GranuCult® Half FRASER broth (base) with antibiotics has high nutrient content and a large buffering capacity that creates optimum growth conditions for Listeria spp. Lithium chloride, nalidixic acid, and acriflavine hydrochloride inhibit the growth of accompanying bacteria. The detection of the β-D-glucosidase activity is possible by adding aesculin and ammonium iron (III) citrate, forming a black complex of aesculin with iron (III) ions. A black coloration can develop during incubation, but this reaction is not exclusive to Listeria spp. Hence, according to EN ISO 11290-1, every primary and secondary enrichment in Fraser broth must be sub-cultured on selective plating media. From GranuCult® Half FRASER (Demi FRASER) Broth (Base) with Antibiotics primary selective enrichment Half Fraser broth can be prepared by addition of one vial Ammonium iron (III) citrate supplement (1.00092) per 500 mL Half Fraser Broth (base). For the secondary enrichment step, Fraser broth can be prepared by adding one additional vial of reconstituted Fraser Listeria selective supplements (1.00093) per 500 mL Half Fraser Broth.
Application
GranuCult® Half FRASER broth (base) with antibiotics is suitable for the primary selective enrichment of Listeria spp. from food and animal feed as well as from environmental samples and other materials.
Analysis Note
Appearance (clearness): clear
Appearance (colour): yellowish-brown
pH-value (25 °C): 7.0 - 7.4
Growth promotion test in accordance with the current version of DIN EN ISO 11133.
Mixed inoculum of Listeria, E.coli and E.faecalis
Additionaly monoculture of E.coli and E.faecalis
Afterwards confirmation on ALOA®-Medium resp. Tryptic Soy agar
Inoculum on reference medium (Listeria monocytogenes ATCC 13932 (WDCM 00021)): ≤ 100
Inoculum on reference medium (Listeria monocytogenes ATCC 35152 (WDCM 00109)): ≤ 100
Inoculum on reference medium (Escherichia coli ATCC 25922 (WDCM 00013)): ≥ 1000
Inoculum on reference medium (Escherichia coli ATCC 8739 (WDCM 00012)): ≥ 1000
Inoculum on reference medium (Enterococcus faecalis ATCC 19433 (WDCM 00009)): ≥ 1000
Inoculum on reference medium (Enterococcus faecalis ATCC 29212 (WDCM 00087)): ≥ 1000
Growth on ALOA medium (Listeria monocytogenes ATCC 13932 (WDCM 00021)): >10 colonies
Growth on ALOA medium(Listeria monocytogenes ATCC 35152 (WDCM 00109)): >10 colonies
Colonies (Listeria monocytogenes ATCC 13932 (WDCM 00021)): blue green colonies with opaque halo
Colonies(Listeria monocytogenes ATCC 35152 (WDCM 00109)): blue green colonies with opaque halo
Growth on Tryptic soy agar (Escherichia coli ATCC 25922 (WDCM 00013)): total inhibition
Growth on Tryptic soy agar (Escherichia coli ATCC 8739 (WDCM 00012)): total inhibition
Growth on Tryptic soy agar (Enterococcus faecalis ATCC 29212 (WDCM 00087)): -Medium: 44 ± 4 hours at 37 ± 1°C
Confirmation on Tryptic Soy Agar: 24 ± 3 hours at 37 ± 1°C
Legal Information
ALOA is a registered trademark of Biolife Italiana S.r.l.
GRANUCULT is a registered trademark of Merck KGaA, Darmstadt, Germany
NutriSelect is a registered trademark of Merck KGaA, Darmstadt, Germany
Disclaimer
We offer two media types: the superior granulated GranuCult® and the cost-efficient powdered NutriSelect® culture media, depending on your needs. The designations basic, plus, or prime are added to indicate the quality control level, from basic quality control to standard QC plus to prime for full regulatory compliance.
