O método trata de en nove tubos colocar 10ml de mostra( 3 tubos), 1ml de mostra( 3 tubos), 0,1ml de mostra ( 3 tubos), previamente esterelizados co medio de cultivo dentro (10ml cada tubo).
Despois desto deben ir a estufa a 44 graos durante 24 horas.
Despois mediante os tubos positivos e a taboa do NMP calculamos a densidade dos coliformes:
| 10 | 1 | 0.1 | NMP/ml | | 10 | 1 | 0.1 | NMP/ml |
| 0 | 0 | 0 | 0 | | 2 | 0 | 0 | 9 |
| 0 | 0 | 1 | 3 | | 2 | 0 | 1 | 14 |
| 0 | 0 | 2 | 6 | | 2 | 0 | 2 | 20 |
| 0 | 0 | 3 | 9 | | 2 | 0 | 3 | 26 |
| 0 | 1 | 0 | 3 | | 2 | 1 | 0 | 15 |
| 0 | 1 | 1 | 6.1 | | 2 | 1 | 1 | 20 |
| 0 | 1 | 2 | 3.2 | | 2 | 1 | 2 | 27 |
| 0 | 1 | 3 | 12 | | 2 | 1 | 3 | 34 |
| 0 | 2 | 0 | 6.2 | | 2 | 2 | 0 | 21 |
| 0 | 2 | 1 | 9.3 | | 2 | 2 | 1 | 28 |
| 0 | 2 | 2 | 12 | | 2 | 2 | 2 | 35 |
| 0 | 2 | 3 | 16 | | 2 | 2 | 3 | 42 |
| 0 | 3 | 0 | 9.4 | | 2 | 3 | 0 | 29 |
| 0 | 3 | 1 | 13 | | 2 | 3 | 1 | 36 |
| 0 | 3 | 2 | 16 | | 2 | 3 | 2 | 44 |
| 0 | 3 | 3 | 19 | | 2 | 3 | 3 | 53 |
| | | | | | | | | |
| 1 | 0 | 0 | 3.6 | | 3 | 0 | 0 | 23 |
| 1 | 0 | 1 | 7.2 | | 3 | 0 | 1 | 39 |
| 1 | 0 | 2 | 11 | | 3 | 0 | 2 | 64 |
| 1 | 0 | 3 | 15 | | 3 | 0 | 3 | 95 |
| 1 | 1 | 0 | 7.3 | | 3 | 1 | 0 | 43 |
| 1 | 1 | 1 | 11 | | 3 | 1 | 1 | 75 |
| 1 | 1 | 2 | 15 | | 3 | 1 | 2 | 120 |
| 1 | 1 | 3 | 19 | | 3 | 1 | 3 | 160 |
| 1 | 2 | 0 | 11 | | 3 | 2 | 0 | 93 |
| 1 | 2 | 1 | 15 | | 3 | 2 | 1 | 150 |
| 1 | 2 | 2 | 20 | | 3 | 2 | 2 | 210 |
| 1 | 2 | 3 | 24 | | 3 | 2 | 3 | 290 |
| 1 | 3 | 0 | 16 | | 3 | 3 | 0 | 240 |
| 1 | 3 | 1 | 20 | | 3 | 3 | 1 | 460 |
| 1 | 3 | 2 | 24 | | 3 | 3 | 2 | 1100 |
| 1 | 3 | 3 | 29 | | 3 | 3 | 3 | >1100 |
