SBG Sulfa Enrichment

Intended Use

SBG Sulfa Enrichment is used for enriching Salmonella prior to isolation procedures.

Summary and Explanation

Salmonellosis continues to be an important public health problem worldwide, despite efforts to control the prevalence of Salmonella in domesticated animals. Infection with non-typhi Salmonella often causes mild, self-limiting illness. The illness results from consumption of raw, undercooked or improperly processed foods contaminated with Salmonella. Many of these cases of Salmonella-related gastroenteritis are due to improper handling of poultry products. Various poultry products are routinely monitored for Salmonella before their distribution for human consumption, but in many instances, contaminated food samples elude detection.

SBG (Selenite Brilliant Green) Sulfa Enrichment is prepared according to the formula described by Stokes and Osborne.⁹ The researchers found that whole egg and egg yolk reduced the selective properties of selenite brilliant green enrichment.¹ They also found that the addition of sulfapyridine (SBG Sulfa Enrichment) restored these selective properties.¹

SBG Sulfa Enrichment is a selective enrichment for the isolation of Salmonella species, especially from egg products. The shell and the contents of the egg at the time of oviposition are generally sterile or harbor very few microorganisms. Contamination of the shell occurs afterwards from nesting material, floor litter and avian fecal matter.^10-12

Principles of the Procedure

Peptone provides the nitrogen, minerals and amino acids in SBG Sulfa Enrichment. Yeast extract is the vitamin source. D-Mannitol is the carbon source to stimulate organism growth. The phosphates act as buffers in the enrichment. Sodium taurocholate, sodium selenite and brilliant green are the selective agents. The selective agents are used to inhibit gram-positive organisms and enteric bacteria other than Salmonella. Sodium sulfapyridine is added to increase selectivity.

User Quality Control

Identity Specifications
SBG Sulfa Enrichment
Dehydrated Appearance: Light beige, free-flowing, homogeneous.
Solution:                       2.42% solution, soluble in purified water. Solution
                                    is green, opalescent, may have a precipitate.
Prepared Appearance:     Green, opalescent without significant precipitate.
Reaction of 2.42%
Solution at 25°C:            pH 7.2 ± 0.2
Cultural Response

SBG Sulfa Enrichment
Prepare the enrichment per label directions. Inoculate and incubate at 35 ± 2°C for 18-24 hours. After incubation, subculture onto plates of MacConkey Agar and incubate at 35 ± 2°C for 18-24 hours.

Formula

SBG Sulfa Enrichment
Approximate Formula* Per Liter
Yeast Extract................................................................ 5.0 g
Peptone....................................................................... 5.0 g
D-Mannitol................................................................... 5.0 g
Sodium Taurocholate..................................................... 1.0 g
Sodium Sulfapyridine..................................................... 0.5 g
Sodium Selenite............................................................ 4.0 g
Dipotassium Phosphate................................................ 2.65 g
Monopotassium Phosphate............................................ 1.02 g
Brilliant Green.............................................................. 5.0 mg
*Adjusted and/or supplemented as required to meet performance criteria.

Directions for Preparation from Dehydrated Product

SBG Sulfa Enrichment
1. Suspend 24.2 g of the powder in 1 L of purified water. Mix thoroughly.
2. Heat with frequent agitation and boil for 5-10 minutes to completely dissolve the powder. Avoid overheating.
DO NOT AUTOCLAVE.
3. Test samples of the finished product for performance using stable, typical control cultures.

Procedure

Refer to appropriate references for specific procedures for the isolation and cultivation of Salmonella from meat, poultry and egg products and other foods.^2,7,8

Expected Results

Examine prepared media for growth. Positive tubes should be subcultured onto prepared media for isolation and identification of bacteria.

Limitations of the Procedure

SBG Sulfa Enrichment should be used in conjunction with a selective prepared medium for bacterial identification.

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