Merck, 67438, <i>C. perfringens</i> Millichrome™plus Agar Base

General description
C. perfringens Millichrome™ plus Agar Base is a selective chromogenic medium used for the detection and enumeration of Clostridium perfringens. The medium contains peptones and yeast extract that provide nitrogenous nutrients for growth, sodium chloride for osmotic balance, chromogenic substrates for color differentiation, and selective agents to inhibit the growth of other organisms. The medium also contains some special growth factors for the growth of C. perfringens, and agar as the solidifying agent.
Application
C. perfringens Millichrome™ plus Agar Base is suitable for the detection and enumeration of Clostridium perfringens.
Preparation Note
Store prepared media below 8°C, protected from direct light (max. 1 month).
Store dehydrated powder, in a dry place, in tightly sealed containers at 2-25°C.

Step 1 (Preparation of the base C. perfringens Millichrome™ plus Agar Base)

Disperse slowly 50.9 g of powder base in 1 L of purified water.
Stir until agar is well thickened.
Heat and bring to boiling (100 °C) while swirling or stirring regularly.
AUTOCLAVE at 121 °C during 15 min.
Mix when removing it from the autoclave.
Cool in a water bath to 45/50 °C, swirling or stirring gently.
Step 2 (Preparation of the Supplement 1)
In a transparent vessel, add 2 g of C. perfringens Millichrome™ plus Agar Base supplement 1 in 20 mL of purified water.
Swirl well until complete dissolution.
Filter to sterilize at 0.45 μm.
Step 3 (Preparation of the Supplement 2)
Add 0.12 g of C. perfringens Millichrome™ plus Agar Base supplement 2 in 1 mL of purified water.
Filter to sterilize at 0.45 μm
Step 4 (Mixing of the prepared base and the supplements 1 and 2)
Add 20 mL/L of the supplement 1 solution to the melted base at 45/50 °C.
Add 1 mL/L of the supplement 2 solution to the melted base at 45/50 °C.
Swirl or stir gently to homogenize.
Pour into sterile Petri dishes
Let it solidify and dry.

Analysis Note
The medium is specific for C. perfringens and can differentiate it from other organisms based on the orange color of the colonies.
Legal Information
MilliChrome is a trademark of Merck KGaA, Darmstadt, Germany