1.03785

Egg yolk tellurite emulsion

pasteurized, 20%, suitable for microbiology

• UNSPSC Code: 41106212
• NACRES: NA.74

Properties

• biological source: chicken egg yolk
• Quality Segment: 200
• agency: APHA, FDA-BAM, ISO 6888
• sterility: sterile
• form: liquid
• CofA: current certificate can be downloaded
• concentration: 20%
• density: 1.02 g/cm³ at 20 °C
• application(s): food and beverages, microbiology
• compatibility: for use with Baird-Parker Agar (Base) (1.05406)
• shipped in: ambient
• storage temp.: 2-8°C

Description

General description

Egg-yolk tellurite emulsion is a stabilized emulsion of egg yolk for microbiological use, which is added directly to nutrient media for the identification of strains of coagulase-positive Staphylococci by their lecithinase activity. Potassium tellurite has a selective activity and allows the growth of Staphylococcus as black colonies. Egg-yolk permits the detection of microbial lecithinase activity and tellurite reduction.

Application

Egg-yolk tellurite emulsion is an additive consisting of an emulsion of egg-yolk used as a supplement to prepare Baird Parker agar base medium for the detection of Staphylococcus.

Analysis Note

Appearance: pale yellow emulsion
Sterility test: sterile
Typical composition: Sterile egg-yolk 200 ml; NaCl 4.25 g; potassium tellurite 2.1 g; distilled water to give a final volume of 1000 ml.
Egg-yolk Tellurite Emulsion tested in BAIRD-PARKER-Agar Art. 1.05406.
Inoculum on reference medium
- Staphylococcus aureus ATCC 25923 (WDCM 00034):
10 - 100
- Staphylococcus aureus ATCC 6538 (WDCM 00032): 10 - 100
Inoculum
- Escherichia coli ATCC 25922 (WDCM 00013):
>10⁴
- Escherichia coli ATCC 8739 (WDCM 00012): >10⁴
- Staphylococcus saprophyticus ATCC 15305 (WDCM 00159): >10⁴
- Staphylococcus epidermidis ATCC 12228 (WDCM 00036): >10⁴
Recovery on test medium
- Staphylococcus aureus ATCC 25923 (WDCM 00034):
≥ 70%
- Staphylococcus aureus ATCC 6538 (WDCM 00032): ≥ 70%
Growth
- Escherichia coli ATCC 25922 (WDCM 00013):
no growth
- Escherichia coli ATCC 8739 (WDCM 00012): no growth
- Staphylococcus saprophyticus ATCC 15305 (WDCM 00159): poor to fair
- Staphylococcus epidermidis ATCC 12228 (WDCM 00036): poor to fair
Colony colour
- Staphylococcus aureus ATCC 25923 (WDCM 00034):
black
- Staphylococcus aureus ATCC 6538 (WDCM 00032): black
- Staphylococcus saprophyticus ATCC 15305 (WDCM 00159): black-grey
- Staphylococcus epidermidis ATCC 12228 (WDCM 00036): black-grey
Clear zones
- Staphylococcus aureus ATCC 25923 (WDCM 00034):
+
- Staphylococcus aureus ATCC 6538 (WDCM 00032): +
- Staphylococcus saprophyticus ATCC 15305 (WDCM 00159): -
- Staphylococcus epidermidis ATCC 12228 (WDCM 00036): -
Incubation: 24 - 48 hrs. at 37°C, E.coli: 48 hrs. Reference: Tryptic soy agar.

Other Notes

Replaces: 1.03785.0007

Strain origin: CECT^® 4972

Other cell culture collections:

DSM 17076

ATCC^® 700728

NCTC 12900

Legal Information

ATCC is a registered trademark of American Type Culture Collection

CECT is a registered trademark of Universitat de Valencia

Safety Information

• Storage Class: 10 - Combustible liquids
• wgk: WGK 2