FOR THE PRESUMPTIVE IDENTIFICATION OF SALMONELLA

 

• Rapid detection of Salmonella spp. within 24–48 hours after enrichment
• Chromogenic differentiation of Salmonella colonies
• Ready-to-use, pre-dried plates – no media preparation required
• Compact format minimizes incubator space and simplifies handling
• Compliant with ISO 6579-1:2017 and FDA BAM Chapter 5 guidelines
• Equivalent sensitivity to conventional agar-based methods
• Room temperature storage for up to 18 months
• Microval Certificate No 2022LR110

 

CompactDry™ SL (Salmonella) is a ready-to-use chromogenic dry medium plate designed for the rapid and presumptive detection of Salmonella species in food, beverage, water, and environmental samples. The selective formulation contains chromogenic substrates that react with Salmonella-specific enzymes, allowing distinct colony color formation. CompactDry™ SL offers a simplified workflow compared to conventional agar methods and enables fast, reliable screening in compliance with ISO 6579-1:2017 and FDA BAM Chapter 5 standards.

Principle of Operation

The CompactDry™ SL plate incorporates a chromogenic substrate that targets the motility and specific enzymatic activities characteristic of Salmonella spp. A pre-enriched sample is inoculated onto the plate according to the kit instructions.

The presence of Salmonella in the sample is detected by the combination of different test principles. Alkalization of the medium by Salmonella’s lysine decarboxylase ability (medium color will change blue purple to yellow). Motile Salmonella will spread across the plate, the blue/purple plate also becomes yellow, mirroring the Salmonella motility. Greening of the colony is caused by decomposition of chromogenic substrate and black/green colonies are generated by the hydrogen sulphide producing Salmonella. Non-Salmonella bacteria are inhibited by the selective agents, allowing clear differentiation of target colonies after incubation. Results can be interpreted visually within 20–24 hours depending on the initial sample load.

 

Test Procedure

1. Perform pre-enrichment of the test sample in Buffered Peptone Water (BPW) at 36+1 °C for 10–24 hours.
2. Using a sterile pipette, inoculate 0.1 mL of the selective enrichment onto one side of the CompactDry™ SL plate, approximately 1cm from the edge of the plate.
3. Using a sterile pipette, gently inoculate 1.0ml mL of sterilized water onto the other side of CompactDry™ SL plate.
4. Replace the lid and allow the water to spread evenly by capillary action.
5. Incubate the inverted plate at 42+1 °C for 20–24 hours.
6. Observe and record results based on media reaction, motility and colony color.

 

Performance and Interpretation

• Alkalization of the medium by Salmonella’s lysine decarboxylase ability (medium color will change blue purple to yellow).
• As motile Salmonella spread across the plate, the blue/purple plate also becomes yellow, mirroring the Salmonella motility.
• Subsequent and/or concomitant greening of the colony is caused by decomposition of chromogenic substrate by a specific Salmonella enzyme.
• Black/green colonies are generated by the hydrogen sulphide producing Salmonella.
• Salmonella Negative No black or green colonies are observed. Caution: If Pseudomonas or Proteus are present the media may change to yellow but the yellow portion is small and limited because of their reduced motility.
• Time to Result: Approximately 40–48 hours total including enrichment.
• For confirmation, suspect colonies should be subjected to biochemical or serological identification tests.

Storage and Shelf Life

• Store at room temperature (2–25 °C)
• Avoid direct sunlight and high humidity
• Shelf life: 18 months from manufacture date
• Each set of 4 plates sealed in foil for sterility
• Do not use after expiry or if seal is damaged.

 

 

Ordering Details

Stock Code: HS1002973          Pack Size: 40

Stock Code: HS1002938          Pack Size: 240

Stock Code: HS1402938          Pack Size: 500

Stock Code: HS1502887          Pack Size: 1400