Staphylococcus aureus Chromogenic Medium is used for food, rapid detection of Staphylococcus aureus in water, milk, ice cream and meat products, the results will turn out within 24 hours. The colonies of Staphylococcus aureus are blue-green, Listeria is purple, and most of Gram-negative bacteria are inhibited.

Ingredients (g/L):

*Adjusted and/or supplemented as required to meet performance criteria.

Directions:

Suspend 17.26g of the medium in 200mL distilled water; boil in 2.-3 minute, when cooling to 50℃ into sterile petri dishes.

Procedures:

Coating method:

1. Prepared sample solution according to national standards, SN standard, FDA standards or other methods.

2. Transfer 1ml sample solution with appropriate dilution onto the center of Staphylococcus aureus chromogenic medium plate of dry surface, each dilution of medium is made into two plates;

3. Coat sample solution to the agar surface with an L-shaped glass rod, avoid to coat on plate edge, put the plate upright until the liquid is absorbed by the sample medium;

4. Put inverted into incubator at 36 ± 1 ℃for 18-24h, typical of Staphylococcus aureus protuberant blue-green colonies;

5. Counting all protuberant blue-green colonies on plate.

Streak method:

1. Prepared sample solution according to national standards, SN standard, FDA standards or other methods.

2. Take 10ul-20ul sample solution, streaked on solidified Staphylococcus aureus chromogenic medium plates

3. Place inverted in incubator culture at 36 ± 1 ℃for 18-24h, typical of Staphylococcus aureus protuberant blue-green colonies

Note: Staphylococcus aureus is Gram-positive cocci by microscopic examination and rabbit plasma coagulase test is positive

Quality Control:

1. Appearance:

The dehydrate powder medium is homogeneous, having good flow ability; pale yellow or pale pink, prepared medium is colorless solid.

2. Microbial sensitivity test:

Incubated at 36 ± 1 ℃ 18-24h:

Typical features:

Typical of Staphylococcus aureus protuberant blue-green colonies; observe the results within 24 hours.

Storage:

The prepared plates can be kept in 2-5 days, avoid direct exposure to light. The powder medium should be placed in a dark, dry place, storage temperature 2-8 ℃, avoid direct exposure to light.

Failure:

Dry powder media which are over the shelf life, caking and color variation cannot be used.

Note:

This medium is only for laboratory use.

Reference:

1. Beckers H. J., van Leusden F. M., Hogeboom W. M. and Delfgon-van Asch E. H. M. (1980) (English summary) De Ware(n)-Chemicals 10. 125-130.Enterobacteriaceae. Ann. Inst. Pasteur (Paris), 102; 267-277 (1962).

2. Beckers H. J., van Leusden F. M., Bindshedler O. and Guerraz D. (1984) Can. J. Microbiol. 30. 470-474.

3.Baird-Parker A. C. (1962) J. Appl. Bacteriol. 25. 12-19