Technical Data
MacConkey Agar w/o Crystal Violet (Powder)
Microbiological Grade
Storage RT    Shipping RT
Formulation in grams per liter:
Pancreatic Digest of Gelatin17.0
Sodium Chloride5.0
Bile Salts Mixture5.0
Casein Digest Peptone1.5
Peptic Digest of Animal Tissue1.5
Neutral Red0.05
Crystal VioletAbsent
Less selective than Macconkey Agar and will permit growth of Enterococci and Staphylococci.
MacConkey Agar without Crystal Violet is a modified version of the first media developed for the isolation of Gram negative enteric bacteria. The deletion of crystal violet allows the growth of enterococci, staphylococci and Mycobacterium sp. Gram negative enteric bacteria which ferment lactose will produce red to pink colonies. Because this medium is less inhibitory medium it is recommended that specimens be plated on other more inhibitory Gram negative media such as Deoxycholate Agar.

Quality Control Specifications:
1. The powder is homogeneous, free-flowing and light pinkish-beige.
2. Visually the prepared medium is clear to slightly hazy and reddish orange.
3. Expected cultural response after 18-24 hours at 35.0C.

Escherichia coli ATCC 25922
Growth, Pink to red colonies

Proteus mirabilis ATCC 12453
Growth, Clear colonies

Salmonella typhimurium ATCC 14028
Growth, Clear colonies

Enterococcus faecalis ATCC 29212
Growth, Pink to red colonies

Storage: Store the sealed bottle containing the dehydrated medium at 2-30C. Once opened and recapped, place the container in a low humidity environment at the same storage temperature. Protect it from moisture and light. The dehydrated medium should be discarded if it is not free flowing or if the color has changed from the original light pinkish-beige color.

Mix 52 grams of the medium in one Liter of purified water until evenly dispersed. Heat with repeated stirring and boil for one minute to dissolve completely. Distribute and autoclave at 121.0C for 15 minutes. Storage and Stability:

Store powdered media at RT. Opened bottles should be capped tightly and kept in a dark, low humidity environment. Prepared media should be kept at 4C and used within a short period of time.

Final pH: 7.4 0.2 at 25.0C Appearance

Solution: Visually the prepared medium is clear to slightly hazy and reddish orange.

Important Note: This product as supplied is intended for research use only, not for use in human, therapeutic or diagnostic applications without the expressed written authorization of United States Biological.