*** Agar Medium J ***

Difco™ Antibiotic Medium 11 / Neomycin Assay Agar
Approximate Formula* Per Liter
Beef Extract : 1.5 g
Yeast Extract : 3.0 g
Peptone : 6.0 g
Dextrose : 1.0 g
Pancreatic Digest of Casein : 4.0 g
Agar : 15 g
*Adjusted and/or supplemented as required to meet performance criteria.

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Selection of Media "Difco™ Antibiotic Medium 11" for the Microbiological Assay of Antibiotics:

ANTIBIOTIC / ASSAY METHOD / ORGANISM / ATCC
Erythromycin / Cylinder Plate / Micrococcus luteus / 9341
Gentamycin / Cylinder Plate / Staphylococcus epidermidis / 12228
Neomycin / Cylinder Plate / Staphylococcus epidermidis / 12228
Paromomycin / Cylinder Plate / Staphylococcus epidermidis / 12228
Sisomicin / Cylinder Plate / Staphylococcus epidermidis / 12228

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Directions for Preparation from Dehydrated Product

1. Suspend the powder in 1 L of purified water: Difco™ Antibiotic Medium 19 – 30.5 g.
2. Heat with frequent agitation and boil for 1 minute to completely dissolve the powder.
3. Autoclave at 121°C for 15 minutes.
4. To raise the pH of Antibiotic Medium 11 to 8.3 ± 0.1, cool the base to 45-50°C and add NaOH.
5. Test samples of the finished product for performance using stable, typical control cultures.

Cylinder Plate Assay
Use 20 × 100 mm glass or plastic Petri dishes with sufficient depth so that cylinders used in the assay will not be pushed into the medium by the cover.

Use stainless steel or porcelain assay cylinders having the following dimensions (± 0.1 mm): 8 mm outside diameter, 6 mm inside diameter and 10 mm long. Carefully clean the cylinders to remove all residues, using an occasional acid bath (i.e., with approximately 2N nitric acid or with chromic acid). Four or six cylinders are generally used per plate, evenly spaced on a 2.8 cm radius.

To assure accurate assays, work on a level surface to obtain uniformly thick base and seed layers in the Petri dish. Allow the base layer to solidify and then overlay the seed layer containing a proper concentration of the test organism. The amount of medium in the layers varies for different antibiotics, with most assays specifying a 21 mL base layer and a 4 mL seed
layer. In any case, dishes with flat bottoms are required to assure complete coverage of the bottom of the dish when small amounts of base medium are used. Tilt the plate to obtain even coverage of the base layer by the seed layer and allow it to solidify in a level position. Plates should be used the same day as prepared.

Poids	0,81 Kg   (810 g)
Volume	0,0056 m³   (5600 cm³)
Largeur	0,15 m   (15 cm)
Longueur	0,15 m   (15 cm)
Hauteur	0,25 m   (25 cm)

Les dimensions, le poids et le volume sont bruts (emballage inclus)