Baird-Parker Agar

Baird-Parker Agar

Selective & Differential Medium for Presumptive Isolation of Staphylococcus aureus

Catalog Number: AS-1130

Overview

Baird-Parker Agar is a selective and differential solid culture medium widely used for the isolation and presumptive identification of coagulase-positive staphylococci, particularly Staphylococcus aureus, from food, pharmaceutical, cosmetic, and environmental samples.

The medium combines a nutrient-rich base with selective agents to suppress competing microflora while promoting characteristic colony morphology of target organisms. When supplemented with egg-yolk emulsion and potassium tellurite, coagulase-positive staphylococci produce distinctive black to grey colonies with surrounding reaction zones, enabling rapid visual differentiation.

Baird-Parker Agar is referenced in international food microbiology standards including ISO 6888-1, ISO 6888-2, and related regulatory methods.

Key Features & Benefits

• Selective isolation of coagulase-positive staphylococci

• Distinctive colony morphology for presumptive identification

• Strong inhibition of competing Gram-negative and background flora

• Widely accepted reference medium in food and pharmaceutical testing

• Reliable and reproducible performance for routine QC workflows

Typical Applications

Food Microbiology

• Detection of Staphylococcus aureus in dairy products, meats, processed foods, and ready-to-eat products

• Routine quality-control testing in food manufacturing

Pharmaceutical & Cosmetic Microbiology

• Monitoring of raw materials and finished products

• Environmental hygiene and contamination assessment

Environmental & Research Laboratories

• Screening of surface and environmental samples

• Method validation and comparative studies

Principle of the Medium

The nutrient base (casein peptone, meat extract, yeast extract) supports staphylococcal growth, while selective agents suppress competing organisms:

• Lithium chloride and potassium tellurite inhibit non-target bacteria

• Glycine and sodium pyruvate enhance recovery of stressed staphylococci

• Tellurite reduction results in grey to black colony coloration

When supplemented with egg-yolk emulsion, coagulase-positive staphylococci typically produce:

• Black or grey colonies

• Clear zones due to lipase activity

• Opaque halos caused by coagulase-associated reactions

These features together provide strong presumptive identification of coagulase-positive staphylococci.

For confirmatory testing, Rabbit Plasma Fibrinogen may be incorporated according to validated methods.

Typical Colony Appearance

(After 24–48 h incubation at 35–37 °C)

• Coagulase-positive staphylococci:
  Smooth, convex, grey to black colonies with clear zones and opaque halos

• Other organisms:
  Inhibited or small, atypical colonies without characteristic reactions

Storage & Stability

Dehydrated medium

• Store at 15–30 °C

• Keep dry and tightly sealed

Prepared medium

• Store at 2–8 °C

• Protect from light and dehydration

Intended Use

For laboratory food, pharmaceutical, environmental, and research microbiology use only.

Not for human, animal, diagnostic, or therapeutic use.

Quality & Compliance

• Performance aligned with ISO 6888 methods

• Manufactured under controlled conditions for batch consistency

• Certificate of Analysis (COA) available

• Safety Data Sheet (SDS) available upon request