ChroMedium Coliforme (CCA)
According to ISO 9308-1:2012
| Shorthand symbol: | CCA |
| Item number: | 40-1064 |
| Format: | Petri Dish, 90mm |
| Colour: | Yellowish, transparent |
| Storage conditions: | Dry, in closed bag at 4 – 10°C. |
| Shelf-life: | 4 Months |
| pH: | 6.8 ± 0.2 at 25°C |
Chromogenic Coliform Medium (CCA) allows the detection and enumeration of total Coliforms and Escherichia Coli for the microbiological analysis of water and food samples. The nutrient medium promotes the rapid growth of coliforms, even in case of sublethal injury. The addition of Tergitol-7 inhibits the growth of Gram Positive bacteria and in some cases Gram Negative bacteria. The short incubation period of less than 24 hours reduces the analysis time when compared to other existing methods.
| in g per 1 Litre Nutrient medium | |
|---|---|
| Casein peptone | 1.0 |
| Yeast Extract | 2.0 |
| Sodium Chloride | 5.0 |
| Sodium hydrogen phosphate | 2.2 |
| Disodium hydrogen phosphate | 2.7 |
| Sodium pyruvate | 1.0 |
| Sorbitol | 1.0 |
| Tryptophan | 1.0 |
| Tergitol-7 | 0.15 |
| 6-Chloro-3-indoxyl-ß-D-galactopyranoside | 0.2 |
| 5-Bromo-4-chloro-3-indoxyl-ß-D-glucuronic acid | 0.1 |
| Isopropyl-ß-D-thiogalactopyranoside (IPTG) | 0.1 |
| *Adjusted as required to meet performance standards |
The Microbiological Performance Test is carried out in accordance with the requirements BS EN ISO 11133:2014 .
Productivity
Incubation conditions: 21±3 hours at 36±2°C; Inoculum concentration: 80–120 CFU
| Organism | Type Strain | Specification | Colony morphology | |
|---|---|---|---|---|
| Escherichia coli | NCTC 13167/WDCM 00179 | 50–130 % | Typical, blueish violet colonies | |
| Enterobacter aerogenes | ATCC 13048/WDCM 00175 | 50–130 % | Typical pink colonies | |
| Citrobacter freundii | ATCC 43864/WDCM 00006 | 50–130 % | Typical pink colonies |
Selectivity
Incubation conditions: 21±3 hours at 36±2°C; Inoculum concentration: 10.000–1.000.000 CFU
| Organism | Type Strain | Specification | Colony morphology | |
|---|---|---|---|---|
| Enterococcus faecalis | ATCC 19433/WDCM 00009 | Complete inhibition | - |
Specificity
Incubation conditions: 21±3 hours at 36±2°C; Inoculum concentration: 1.000–10.000 CFU
| Organism | Type Strain | Specification | Colony morphology | |
|---|---|---|---|---|
| Pseudomonas aeruginosa | ATCC 27853/WDCM 00025 | Good growth | White, green colonies |
Microbial Contamination
Incubation conditions: 5–7 days at 20–25°C and 5–7 days at 30–35 °C
| Specification |
|---|
| No microbial contamination |