6.4.2.4 Tests for microbial quality
Make a total viable count by membrane filtration of not less than 100 ml final rinse water sample. Place the filter on R2A-medium in accordance with Annex D, or other suitable low nutrient medium and incubate at 28 °C to 32 °C for a minimum of 5 days to determine the aerobic mesophillic viable count.
Other methods, including rapid methods such as ATP bioluminescence, that have been validated to be at least equivalent to the above method in terms of both specificity and sensitivity can also be used.