Cooked Meat Granules

(for Cooked Meat Medium)

Method for reconstitution

Weigh 41 grams of powder, disperse in 1 litre of deionised water. Allow to soak for 10 minutes, swirl to mix then sterilise by autoclaving for 15 minutes at 121˚C. Cool to 48˚C and add 5-7% sterile, defibrinated horse or sheep blood. Mix well before pouring.

Appearance: Cherry red if blood is fresh and well oxygenated.

pH: 7.3 ± 0.2

Minimum Q.C. organisms: S. aureus

NCIMB 50080 S. pyogenes ATCC 19615

Storage of Prepared Medium: Plates - up to 7 days at 2-8˚C in the dark.

Inoculation: Surface plating, streaking out for single colonies.

Incubation: 37˚C aerobically or microaerobically for 24 hours. Anaerobically for 24 and 48 hours.

Description

Dried minced ox heart which has been trimmed of excess fat and prepared according to the Martin and Lekpers modification of Robertsons original formulation. The medium gives good growth of most organisms and is especially useful in the recovery of fastidious anaerobes. The medium is also suitable for prolonged storage of cultures.

Method for reconstitution

To make Cooked Meat Medium the granules should be added to Nutrient Broth (LAB 14) or Fastidious Anaerobe Broth (LAB 71) in the ratio of 15 grams of granules to 200ml of broth. Cooked Meat Medium should be dispensed into containers allowing at least 20­25mm depth of meat particles and a broth supernatant of at least 10­15mm. To sterilise autoclave at 121˚C for 15 minutes in capped tubes which should be tightened after autoclaving to prevent re-oxygenation.

Medium prepared with Nutrient Broth LAB 14 should be re-steamed when used after a period of storage. Medium made with Fastidious Anaerobe Broth LAB 71 will not require re-steaming after storage.

Storage of Prepared Medium: - up to 6 months at 15-20˚C in the dark.

References

Cruickshank, R. 1972. Medical Microbiology. 11th Edn. Livingstone, London.