Ready-to-use Columbia CNA blood agar plate, 90 mm, for hemolytic streptococci isolation

Columbia CNA Blood Agar Plate 90 mm – Ready-to-Use Selective Medium for Hemolytic Streptococci (Pack of 10)

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Columbia CNA Blood Agar is a selective culture medium used in food, dairy, environmental and laboratory microbiology for the selective isolation of hemolytic streptococci and other Gram-positive cocci. This ready-to-use prepared blood agar plate saves preparation time, reduces contamination risk and delivers consistent, batch-controlled performance.

Selective & differential design

  • Sterile defibrinated sheep blood supports hemolysis and colony development.
  • Polymyxin (colistin) and nalidixic acid suppress most Gram-negative bacteria, while Gram-positive cocci such as hemolytic streptococci grow well.
  • Hemolytic activity is easy to observe directly on the blood agar surface.

Ready-to-use & reliable

  • Supplied as 90 mm prepared plates, 20–25 mL agar per plate.
  • Triple-layer sterile packaging helps protect the medium and reduce condensation and dehydration.
  • Sterility and growth controls are performed: typical growth of Staphylococcus aureus, Listeria monocytogenes and alpha-hemolytic streptococci; Escherichia coli and Pseudomonas aeruginosa are inhibited.
  • Consistent gel strength (500–650 g/cm²) and controlled pH (7.1–7.5).

Typical composition (per litre)

  • Pancreatic digest of casein 12.0 g; Animal tissue digest 5.0 g; Yeast extract 3.0 g; Beef extract 3.0 g; Corn starch 1.0 g; Sodium chloride 5.0 g; Agar 13.5 g; Polymyxin 0.01 g; Nalidixic acid 0.01 g; Sterile defibrinated sheep blood 50 mL; Purified water 1000 mL; final pH 7.3 ± 0.2.

Storage & shelf life

  • Store upright at 2–8 °C, protected from light.
  • Shelf life: 3 months (90 days) from production.
  • Avoid temperature swings over 10 °C, which can cause condensation.

How to use

  1. Remove the plate from cold storage and allow it to equilibrate to room temperature (place upright 4–6 hours before use to reduce surface moisture).
  2. Transport the whole pack to the test site.
  3. Inoculate and incubate inverted at the specified temperature and time.
  4. Observe and count colonies.

Quality indicators

  • Appearance: blood-red, smooth, no cracks, no visible impurities or bubbles.
  • pH 7.1–7.5; gel strength 500–650 g/cm².
  • Sterility: no growth after incubation for 2 days.
  • Growth: S. aureus, L. monocytogenes and alpha-hemolytic streptococci – typical colony size and characteristics; E. coli, P. aeruginosa – inhibited.

Note

  • For microbiological testing only. Not for clinical diagnosis. Single-use product; autoclave before disposal.
  • Do not use plates that are cracked, dry or contaminated.
  • Minor droplets or moisture inside the pack do not affect normal use; excess moisture can be removed under sterile conditions.

Packaging

  • 90 mm × 10 plates per pack, triple-layer sterile packaging

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