(AB) SIM Medium, 500 grams

The SIM medium is formulated to detect sulfide production, indole formation and motility. Ferrous ammonium citrate and sodium thiosulfate are used to detect hydrogen sulfide production. H2S gas reacts with ferrous ammonium citrate to produce ferrous sulfide, a black precipitate. Casein peptone contains tryptophan which is converted to indole. lndole is detected after incubation by the addition of Kovac's reagent which reacts with indole to produce a red color. The medium is semi-solid due to a low concentration of agar and motility is easily seen by growth radiating from original stab. SIM Medium is a semisolid medium used for the determination of indole formation, sulfide production and motility of the Enterobacteriaceae, especially Salmonella and Shigella. (Alpha Biosciences # S19-110-500gm)

Use: SIM Medium is a semisolid medium used for the determination of indole formation, sulfide production and motility of the Enterobacteriaceae, especially Salmonella and Shigella.

Description: The SIM medium is formulated to detect sulfide production, indole formation and motility. Ferrous ammonium citrate and sodium thiosulfate are used to detect hydrogen sulfide production. H2S gas reacts with ferrous ammonium citrate to produce ferrous sulfide, a black precipitate. Casein peptone contains tryptophan which is converted to indole. lndole is detected after incubation by the addition of Kovac's reagent which reacts with indole to produce a red color. The medium is semi-solid due to a low concentration of agar and motility is easily seen by growth radiating from original stab.

Formula* per Liter:

• Casein Digest Peptone................ 20.0g
• Ferrous Ammonium Sulfate ......... 0.2g
• Peptic Digest of Animal Tissue ..... 6.1g
• Sodium Thiosulfate ....................... 0.2g
• Agar ..................................................3.5g

Final pH: 7.3 ± 0.2 at 25.0°C

* Grams per liter may be adj. or formula supplemented to obtain desired performance

Preparation: Mix 30 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 121.0°C for 15 minutes.

Quality Control Specifications:

1. The powder is homogeneous, free-flowing and light beige.
2. Visually the prepared medium is clear to trace hazy and light amber.
3. Expected cultural response after 18-24 hours at 35.0°C.

Organism                                                                  Result ( Ind / Mot / H2S )

Escherichia coli ATCC 25922                                      Growth, ( + / + / - )

Salmonella typhiATCC 19430                                      Growth, ( - / + / + )

Salmonella typhimurium ATCC 14028                         Growth, ( - / + / + )

Shigella flexneri ATCC 12022                                      Growth, ( - / - / - )

Storage: Store the sealed bottle containing the dehydrated medium at 2 to 30.0°C. 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 beige color.