Paragraph
Table A
Parameters for which, subject to regulation 31(4), methods of analysis are prescribed
| (1)Parameter | (2)Method |
|---|---|
| Clostridium perfringens (including spores) | Membrane filtration followed by anaerobic incubation of the membrane on m–CP agar(i) at 44 ± 1°C for 21 ± 3 hours. Count opaque yellow colonies that turn pink or red after exposure to ammonium hydroxide vapours for 20 to 30 seconds. |
| Coliform bacteria | ISO 9308–1 |
| Colony count 22°C – enumeration of culturable micro-organisms | prEN ISO 6222 |
| Enterococci | ISO 7899–2 |
| Escherichia coli (E.coli) | ISO 9308–1 |
(i)
The composition of m–CP agar is:
Basal medium
Tryptose 30g Yeast extract 20g Sucrose 5g L–cysteine 1g MgSO4 . 7H2O 0.1g Bromocresol purple 40mg Agar 15g Water 1,000ml Dissolve the ingredients of the basal medium, adjust pH to 7.6 and autoclave at 121°C for 15 minutes. Allow the medium to cool and add:
D–cycloserine 400mg Polymyxine–B–sulphate 25mg Indoxyl–β-D-glucoside
to be dissolved in 8ml sterile water before addition
60mg Filter – sterilised 0.5% phenolphthalein disphosphate solution 20ml Filter – sterilised 4.5% FeC13 . 6H2O 2ml