BG Sulfa Agar

BG Sulfa Agar (Brilliant Green Agar with Sulfapyridine)

Selective Medium for Isolation of Salmonella Species

Catalog Number: AS-1136

Overview

BG Sulfa Agar (Brilliant Green Agar with Sulfapyridine) is a highly selective solid culture medium designed for the isolation and enumeration of Salmonella species, excluding S. Typhi and S. Paratyphi, from food, feed, environmental, and selected laboratory samples.

The combined action of brilliant green dye and sulfapyridine provides strong inhibition of Gram-positive organisms, Proteus, Pseudomonas, and most coliform bacteria, while allowing reliable recovery of non-typhoidal Salmonella. BG Sulfa Agar is recognised as an official reference plating medium in FDA-BAM Chapter 5 and is recommended in ISO 6579-1 as a supplementary plating medium alongside XLD, HE, and Bismuth Sulfite agars.

Ausamics BG Sulfa Agar is formulated for high selectivity, clear colony differentiation, and reproducible performance in routine and high-throughput food microbiology laboratories.

Key Features & Benefits

• Brilliant green and sulfapyridine provide strong suppression of background flora

• Distinctive pink-red colonies typical of Salmonella spp.

• Transparent medium for easy colony recognition

• Superior recovery of stressed Salmonella compared with older formulations

• Widely used reference medium in FDA-BAM and ISO workflows

Typical Applications

Food Microbiology

• Direct plating for Salmonella in poultry, egg products, dairy, spices, chocolate, and processed foods

• Confirmatory plating following selective enrichment

Regulatory & Reference Testing

• Official FDA-BAM Chapter 5 method

• Recommended supplementary medium in ISO 6579-1

High-Throughput Laboratories

• Parallel plating with XLD, HE, and BS agars

• Routine quality-control and compliance testing

Principle of the Medium

BG Sulfa Agar contains lactose and sucrose as fermentable carbohydrates and phenol red as a pH indicator. Selectivity is achieved through:

• Brilliant green dye, which inhibits Gram-positive bacteria and many Gram-negative competitors

• Sulfapyridine, which enhances suppression of coliforms and Proteus spp.

Salmonella spp., which do not ferment lactose or sucrose, form pink-red to red colonies, while competing organisms are inhibited or produce atypical growth.

Composition (Typical – per litre)

• Yeast extract: 3.0 g

• Proteose peptone: 10.0 g

• Lactose: 10.0 g

• Sucrose: 10.0 g

• Sodium chloride: 5.0 g

• Phenol red: 0.08 g

• Brilliant green: 0.0125 g

• Sodium sulfapyridine: 1.0 g

• Agar: 20.0 g

Final pH at 25 °C: 6.9 ± 0.2

Preparation (Typical)

• Suspend 59 g of dehydrated medium in 1 L purified water

• Heat with frequent agitation and boil for 1 minute until completely dissolved

• Do not autoclave (dyes are heat-labile)

• Cool to 45–50 °C, mix well, and pour into sterile Petri dishes

Typical Colony Appearance

(After 18–24 h incubation at 35–37 °C)

• Salmonella spp. (non-typhi):
  Pink-red to red colonies, 1–3 mm, smooth and well-defined

• Coliforms and Proteus:
  Inhibited or very small yellow-green colonies

• Gram-positive bacteria:
  Completely inhibited

Storage & Stability

Dehydrated medium

• Store below 30 °C in a cool, dry place

Prepared plates

• Store at 2–8 °C, protected from light

• Use within 7 days

Intended Use

For laboratory food, feed, and environmental microbiology use only.

Not for human or animal therapeutic use.

Quality & Compliance

• Official plating medium in FDA-BAM Chapter 5

• Recommended supplementary medium in ISO 6579-1

• Manufactured under controlled conditions for batch consistency

• Certificate of Analysis (COA), Safety Data Sheet (SDS), and Technical Data Sheet (TDS) available upon request