BD Difco™ Agar, Technical

Technical Agar is suitable for many bacteriological applications. This agar is not highly processed, has broader technical specifications than other agars and is not recommended for growth of fastidious organisms. It shows good cultural response (in nutrient broth) to Escherichia coli 25922 and Staphylococcus aureus 25923.

• Loss on Drying (LOD): ≤20%
• Ash(%): ≤6.5%
• Calcium μg/g (ppm): ≤3,000 ppm
• Magnesium μg/g (ppm): ≤1,300 ppm
• Melting Point: ≤85°C
• Gelation Point: 32–39°C
• Gel Strength: 613g/cm³
• pH (1.5% solution, 25°C): 5.9
• Spore count: 4,300 CFU/g
• Standard plate count: 2,725 CFU/g
• Inorganics: Calcium 0.110%, Chloride 0.172%, Cobalt <0.001%, Copper <0.001%, Iron 0.002%, Lead <0.001%, Magnesium 0.093%, Manganese <0.001%, Nitrate <0.005%, Phosphate 0.015%, Potassium 0.124%, Sodium 0.932%, Sulfate 0.367%, Sulfur 0.646%, Tin <0.001%, Zinc <0.001%

Agar is a phycocolloid extracted from a group of red-purple marine algae (Class Rhodophyceae). Agar is the gelling agent of choice because it remains firm at growth temperatures for many pathogens. It is also resistant to a breakdown by bacterial enzymes. Agar melts at a different temperature than that at which it solidifies, a property known as hysteresis. It is generally resistant to shear forces; however, different agars may have different gel strengths. Agar is typically used in a final concentration of 1–2% for solidifying culture media.