Water quality

The bullet points on this page are an informal compilation of opinions of contributors to the online VOLE List. As such, they are not peer reviewed and may contain differences of opinion. Those wishing to contact the list may contact Adrian Smith.

When testing the water quality offered to your rodents, what would you use as a cut of point where the water is not suitable for research animals? Knowing that 0 CFUs is achievable, would you accept any bacterial count? What systems do you use to treat water and would you recommend any systems?

• When I worked for the Unilever company we had to do nutritional studies according to GLP. We did a study on drinking water bacteriological quality and acidification. This was published in the Scandinavian Journal for Laboratory Animal Science in 1998. It was our general experience that even though you have sterile bottles and sterile water to begin with, within a couple of hours in the animal room you will find high counts of non-pathogenic bacteria within these water bottles, even when animals did not touch them. In our experience high counts were not detrimental to the animals and did not adversely influence nutritional results, as far as we could tell of course. So we did accept bacterial counts, as long as we did not find pathogens. And within the GLP system every finding had to be reported, so you can always go back to these findings.
• In conventional facilities with generally immunocompetent strains, I follow the recommendations for human drinking water (coliforms and E.coli). In addition I recommend TVC at 22C and 37C. There is no standard acceptable value for TVC results, though I have used 100 cfu/ml as a "review" flag. Use it for trending over time to monitor the continuing performance of the distribution system.