Campylobacter spp. is a serious food pathogen. If you are looking for this pathogen, you want to detect this bacteria down to the last cell.
The growth on mCCDA is part of the analysis. Besides the incubation conditions, the quality of the mCCDA medium is crucial to the analysis.
There are two ISO methods available for food analyses, which this medium is mentioned:
– ISO 10272-1 Detection method
– ISO 10272-2 Enumeration method
Modified Charcoal Cefoperazone Deoxycholate Agar (mCCDA) is a blood-free medium to isolate Campylobacter spp. selectively.
mCCDA contains a lot of ingredients. These ingredients must be of good quality and quantity for Campylobacter to grow well.
mCCDA (Modified Charcoal Cefoperazone Deoycholate Agar) medium contains the following ingredients:
- Nutrient broth – nitrogen, vitamin, and mineral source
- Casein hydrolysate – nitrogen, vitamin, and mineral source
- Bacteriological charcoal – absorbs toxic substances and metabolites
- Sodium deoxycholate – inhibits gram-negative enteric bacteria except Campylobacter spp.
- Ferrous sulfate – iron(II) sulfate, which neutralizes toxic oxygen products
- Sodium pyruvate – neutralizes toxic oxygen products
- Amphotericin – inhibits yeast and fungi
- Cefoperazone – inhibits gram-negative enteric bacteria except Campylobacter spp.
- Agar
- Water
Final pH 7.4 ± 0.2
Incubation conditions
44h±4h at 41.5°C±1°C under microaerobic conditions.
Appearance on mCCDA
Typical colonies are greyish on mCCDA, often with a metallic sheen. They are flat and moist and tend to spread, but they tend to spread less on drier agar surfaces.
Electivity on mCCDA of different media suppliers
Research shows a difference in selectivity between suppliers using the same Certified Reference Material – Campylobacter jejuni (CRM-CJ) under the same incubation conditions.
All three suppliers declare that the mCCDA is made according to ISO 10272, but its appearance is diverse.
Sometimes, the colonies are significantly smaller than the other. Smaller colonies can be missed because they are not characteristic enough.
Most likely, the basic ingredients have different origins. This could explain the differences.
If you have doubts about the selectivity of the colony on mCCDA, it is worth trying another mCCDA media supplier to test their selectivity on the mCCDA.
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