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Demi-Fraser Broth Base|正品进口
For use with Fraser Broth Supplement in selectively and differentially enriching Listeria. Reduced Acriflavine and Nalidixic Acid levels.
原理及过程：
Peptone, beef extract and yeast extract provide carbon and
nitrogen sources and the cofactors required for good growth
of Listeria. Sodium phosphate and potassium phosphate
buffer the medium. Selectivity is provided by lithium chloride,nalidixic acid and acriflavine. The high sodium chloride concentration of the medium inhibits growth of enterococci.All Listeria species hydrolyze esculin, as evidenced by a blackening of the medium. This blackening results from the formation of 6,7-dihydroxycoumarin, which reacts with ferric ions.Ferricions are added to the final medium as ferric ammonium citrate in Fraser Broth Supplement.
1. Pre-enrich the sample in Demi-Fraser Broth. Incubate for
18-24 hours at 35 ± 2°C. Subculture onto Oxford Medium
or PALCAM Medium.
2. Transfer 0.1 mL of the pre-enrichment culture into 10 mL of
Fraser Broth and incubate for 48 hours at 37°C. Subculture
onto Oxford Medium or PALCAM Medium after 18-24
hours and again after 42-48 hours of incubation.
3. Examine Oxford Medium or PALCAM Medium plates for
the appearance of presumptive Listeria colonies.
4. Confirm the identity of all presumptive Listeria by
biochemical and/or serological testing.
预期结果：
The presence of Listeria is presumptively indicated by the
blackening of Demi-Fraser Broth after incubation for 24-48
hours at 35°C. Confirmation of the presence of Listeria is made following subculture onto appropriate media and biochemical/serological identification.
用途：
黛米弗雷泽肉汤基础是用来与弗雷泽肉汤灵巧表示“方法”在选择性和差异丰富的李斯特菌食物。 |