CHROMagar™ Listeria Kit, 5000 mL Pack (Base medium + Supplement)

For Detection and Enumeration of Listeria monocytogenes in Food and Environmental Samples

CHROMagar™ Listeria is a selective chromogenic culture medium designed for the isolation, detection, and enumeration of Listeria monocytogenes in food products and production environments. The medium allows the clear visual differentiation of L. monocytogenes from other Listeria species based on colony color and morphology.

This medium overcomes the limitations of traditional Listeria culture media (e.g., Palcam and Oxford agar), which cannot distinguish between L. monocytogenes and L. innocua, providing a faster and more accurate screening solution for food safety and microbiological quality control.

🔹 Key Features & Benefits

• ✅ Species-Level Differentiation:
  • L. monocytogenes appears as blue colonies (<3 mm) surrounded by a white halo, caused by phospholipase activity—unlike L. innocua, which lacks the halo.
• ✅ High Specificity and Accuracy: Easily differentiates between pathogenic and non-pathogenic Listeria species directly on primary isolation media.
• ✅ Clear and Easy Reading:
  • Contrasts sharply with the darker backgrounds of Palcam or Oxford agar.
  • Distinct blue colonies and halo simplify interpretation, even in mixed microbial populations.
• ✅ Compatible with ISO Workflow:
  • Can be used after standard Half Fraser broth enrichment.
  • Confirmation of L. monocytogenes is possible with CHROMagar™ Identification Listeria.
• ✅ Improves Detection and Enumeration: Streamlines QC testing in food industries, especially for ready-to-eat products, dairy, and raw meats.

🔹 Colony Appearance

🔹 Intended Use

CHROMagar™ Listeria is intended for:

• Detection and enumeration of Listeria monocytogenes in:
  • Raw and processed foods
  • Environmental swabs and surfaces
  • Production water and sanitation verification samples
• Microbiological quality control in food processing facilities
• Outbreak surveillance and routine monitoring of hygiene indicators

⚠️ Not intended for diagnostic use in clinical specimens. Further confirmation (e.g., MALDI-TOF, PCR, biochemical tests) is recommended for suspect colonies.

🔹 Test Workflow (Recommended Protocol)

1. Pre-enrichment: Incubate sample in Half Fraser broth for 24 hours
2. Inoculation: Streak broth onto CHROMagar™ Listeria
3. Incubation:
   • Temperature: 35–37 °C
   • Time: 24–48 hours
4. Interpretation:
   • Blue colonies with white halo → L. monocytogenes
   • Blue colonies without halo → Other Listeria spp.

Optional: Confirm L. monocytogenes identity with CHROMagar™ Identification Listeria

🔹 Ordering Information

🔹 Storage & Shelf Life

• Storage Conditions: 2–8 °C, dry and sealed
• Shelf Life: Up to 24 months from manufacture
• Prepared Media: Use within the validated period as per instructions

🔹 Scientific Publications

• Lüthje et al., 2023 – MALDI-TOF MS identification from chromogenic media
• Jamali et al., 2013 – Comparative detection of Listeria spp. in ready-to-eat foods (Food Control, Univ. of Malaya)
• CHROMagar™, 2003 – Numeration method validation report

CHROMagar™ Listeria is a powerful chromogenic medium for the accurate detection and enumeration of Listeria monocytogenes—providing faster, clearer, and more reliable results than traditional media. Its species-level differentiation, visual clarity, and compatibility with international testing protocols make it an essential choice for food safety testing laboratories and food industry quality assurance programs.