Description
Salmonella Shigella Agar (SS) is an essential laboratory medium designed for the selective isolation and differentiation of pathogenic enteric bacilli, specifically from the genera Salmonella and Shigella. This moderately selective and differential media is widely used in microbiology laboratories, food safety testing, and clinical diagnostics due to its ability to inhibit gram-positive bacteria while allowing the growth of gram-negative pathogens.
Key Features:
- Selective Media for Pathogenic Bacteria: Contains bile salts and brilliant green, which inhibit the growth of undesired gram-positive organisms. Ideal for isolating Salmonella and Shigella from food samples and clinical specimens.
- Lactose Fermentation Indicator: The inclusion of lactose allows for differentiation between lactose fermenters, which form red colonies, and non-fermenters, which remain colorless. This feature is crucial in identifying enteric pathogens quickly and effectively.
- Hydrogen Sulfide Detection: The sodium thiosulfate and ferric citrate components enable detection of hydrogen sulfide production, indicating the presence of specific pathogens via black-centered colonies.
Approximate Formula (gm/liter):
- Beef Extract: 5.0
- Sodium Thiosulfate: 8.5
- Proteose: 5.0
- Ferric Citrate: 1.0
- Lactose: 10.0
- Neutral Red: 0.025
- Bile Salt No.3: 8.5
- Brilliant Green: 0.00033
- Sodium Citrate: 8.5
- Agar: 17.0
- Final pH: 7.0±0.2 at 25℃
Directions for Use:
To prepare Salmonella Shigella Agar, suspend 63.53g of the medium in 1 liter of distilled or deionized water. Mix well and boil for one minute to ensure complete dissolution. Do not autoclave. Cool the medium to approximately 45-50℃ and pour into Petri dishes. Allow plates to dry for about 2 hours with covers partially removed for optimal results.
Applications:
Salmonella Shigella Agar is ideal for microbiological studies focusing on enteric infections. Its selective nature makes it indispensable in food microbiology, particularly for detecting pathogens in raw meat, poultry, and dairy products. This medium is essential for ensuring food safety and public health by effectively isolating harmful bacteria.
Storage Conditions and Shelf Life:
Store Salmonella Shigella Agar tightly capped in its original container at 5-30°C. The dehydrated medium has a shelf life of 3 years from the date of manufacture, while prepared medium can be stored out of direct light at 2-8°C.
Quality Control:
For quality assurance, inoculate and incubate at 36±1℃ for 18-24 hours. Regular quality checks ensure the reliability and performance of the medium in isolating Salmonella and Shigella effectively.
Reviews
There are no reviews yet.