Liver Veal Agar is used for cultivating anaerobic bacteria.
Spray1 described a procedure using the anaerobic culture dish for the cultivation of these organisms. Liver Veal Agar is identical to the medium described by Spray.2 Liver Veal Agar provides a rich supply of nutrients for anaerobic and fastidious aerobic pathogens. The medium supports excellent growth of sporulating anaerobes and can be used for deep tube cultures.
Liver Veal Agar is specified in the FDA Bacteriological Analytical Manual (BAM)3 and Compendium of Methods for the Microbiological Examination of Foods.4 Liver Veal Agar can be supplemented with 50% egg yolk for the cultivation of anaerobic organisms.3-5
Infusions, peptones, gelatin and isoelectric casein provide the rich nitrogen, amino acids and vitamin content of the medium. Soluble starch is added to enhance the growth of anaerobes and dextrose is a carbon source. Sodium chloride maintains osmotic balance and agar is the solidifying agent.
Identity Specifications
Liver Veal Agar
Dehydrated Appearance: Light beige, free-flowing, homogeneous.
Solution: 9.7% solution, soluble in purified water upon
boiling. Solution is medium to dark amber,
opalescent, may have a slight precipitate.
Prepared Appearance: Medium to dark amber, opalescent, may have a
slight precipitate.
Reaction of 9.7%
Solution at 25°C: pH 7.3 ± 0.2
Cultural Response
Liver Veal Agar
Prepare the medium per label directions. Inoculate and incubate at 35 ± 2°C for 18-48 hours under appropriate atmospheric conditions. Incubate clostridia anaerobically, Neisseria under increased CO2 and streptococci aerobically.
ORGANISM | ATCC™ | INOCULUM CFU |
RECOVERY |
Clostridium botulinum | 3502* | 102-103 | Good |
Clostridium tetani | 10779* | 102-103 | Good |
Neisseria meningitidis | 13090 | 102-103 | Good |
Streptococcus pneumoniae | 6305 | 102-103 | Good |
*Minimally, one strain of these clostridia should be used for performance testing. These ATCC strains should be used if available.
Liver Veal Agar
Approximate Formula* Per Liter
Liver, Infusion from 50 g............................................... 9.0 g
Veal, Infusion from 500 g.............................................. 6.4 g
Proteose Peptone........................................................ 20.0 g
Gelatin....................................................................... 20.0 g
Soluble Starch............................................................. 10.0 g
Isoelectric Casein.......................................................... 2.0 g
Dextrose...................................................................... 5.0 g
Neopeptone.................................................................. 1.3 g
Tryptone....................................................................... 1.3 g
Sodium Chloride............................................................ 5.0 g
Sodium Nitrate.............................................................. 2.0 g
Agar........................................................................... 15.0 g
*Adjusted and/or supplemented as required to meet performance criteria.
1. Biosafety Level 2 practices, containment equipment and facilities are recommended for activities with clinical specimens of human or animal origin containing or potentially containing C. botulinum or C. tetani or their toxins.
2. Biosafety Level 3 practices, containment equipment and facilities are recommended for all manipulations of cultures of C. botulinum and for activities with a high potential for aerosol or droplet production, and those involving production quantities of toxin.
1. Suspend 97 g of the powder in 1 L of purified water. Mix thoroughly.
2. Heat with frequent agitation and boil for 1 minute to completely dissolve the powder.
3. Autoclave at 121°C for 15 minutes.
4. Test samples of the finished product for performance using stable, typical control cultures.
For a complete discussion of the isolation and identification of anaerobic bacteria and other fastidious aerobic pathogens, refer to the procedures described in Clinical Microbiology Procedures Handbook7 and Manual of Clinical Microbiology.8
Refer to appropriate references and procedures for results.
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