CHROMagar™ B. cereus, for 5L of Liquid Medium

For Detection and Enumeration of Bacillus cereus Group in Food and Environmental Samples

CHROMagar™ B. cereus is a selective chromogenic culture medium designed for the detection, enumeration, and presumptive identification of the Bacillus cereus group from food, environmental, and clinical specimens. Colonies of B. cereus appear as intense blue colonies surrounded by a white halo, allowing for easy and reliable differentiation even in the presence of high background flora.

This medium overcomes the limitations of conventional mannitol-based media (e.g., MYP or Mossel agar), which rely on fermentation profiles and require egg yolk emulsion. CHROMagar™ B. cereus enables direct, clear interpretation in just 24 hours without additional supplements, improving workflow efficiency and diagnostic accuracy.

🔹 Key Features & Benefits

• ✅ Distinct Blue Colonies with White Halo: Enables unambiguous identification of Bacillus cereus group even in complex food matrices.
• ✅ Rapid Detection: Results available after 24 hours of incubation at 30 °C.
• ✅ No Egg Yolk Emulsion Required: Unlike MYP or Mossel agar, the medium does not require additional egg yolk supplementation.
• ✅ High Specificity & Sensitivity:
  • 100% sensitivity and 100% specificity (Adria Normandie Study, 2012)
• ✅ Longer Shelf Life: Prepared plates have a longer usability window compared to conventional media (e.g., MYP with 5-day shelf life).
• ✅ Superior to Classical Media: Better readability, recovery, and selectivity than traditional MYP or Mossel agar.

🔹 Colonies Appearance

🔹 Intended Use

CHROMagar™ B. cereus is intended for:

• Detection and enumeration of the Bacillus cereus group in:
  • Prepared foods (rice, vegetables, meats)
  • Dried foods (spices, cereals, powdered mixes)
  • Environmental samples (e.g., food processing equipment)
• Presumptive identification of both diarrheal and emetic forms of B. cereus associated with foodborne illness
• Surveillance testing in food safety laboratories and quality control workflows

⚠️ This medium is not intended for direct diagnosis or to guide treatment of infections. Confirmatory testing should be performed on suspect colonies.

🔹 Performance & Background

Bacillus cereus is a spore-forming, toxin-producing bacterium frequently implicated in foodborne illnesses, particularly through reheated rice dishes and contaminated spices or dried products. It causes:

• Emetic form (1–6 hr incubation) – linked to improperly stored rice
• Diarrheal form (8–16 hr incubation) – associated with meat, vegetables, and legumes

Traditional MYP agar poses difficulties in differentiating colonies due to mannitol fermentation and dense background flora. CHROMagar™ B. cereus improves selectivity, readability, and reliability using chromogenic substrate technology.

🔹 Test Procedure

1. Sample Types: Food, powdered products, environmental swabs, stool (for clinical surveillance)
2. Inoculation: Direct plating or after enrichment (if necessary)
3. Incubation:
   • Temperature: 30 °C
   • Time: 24 hours in aerobic conditions
4. Interpretation:
   • Blue colonies with white halo → presumptive B. cereus
   • Other bacteria → inhibited or non-specific color

🔹 Ordering Information

🔹 Storage & Shelf Life

• Store prepared or dehydrated components at 2–8 °C, dry and protected from light
• Shelf life: Up to 24 months under proper storage conditions
• Prepared media: Longer shelf life than MYP or Mossel agar (which typically lasts 5 days)

CHROMagar™ B. cereus provides a fast, easy-to-read, and highly reliable solution for the detection and enumeration of the Bacillus cereus group, including strains responsible for emetic and diarrheal foodborne illnesses. With distinctive colony coloration, no need for egg yolk emulsion, and proven 100% sensitivity and specificity, this medium is ideal for food safety labs, quality control testing, and public health surveillance.