Posted 02 February 2013 - 05:30 AM
We have another corrective action in regards to testing our water source (to clean equpiment) for micro. The plan that we submitted was to send our water with a contract lab for micro. Our auditor wanted more information as to what our water spec would be. I tried looking for regulations and EPA if they have a criteria for water spec for cleaning. Is there anyone that can help me with this?
Thank you!
Hi there,
WHO have guidelines for water quality, a couple of example pages attached.
WHO Drinking Water Guidelines page 122.pdf 181.08KB
105 downloads
WHO Drinking Water Guidelines page 130.pdf 236.73KB
84 downloadsAre you extracting your own water? if not your supplier should provide a specification for the water they are supplying.
Normally you would monitor incoming water and at point of use, you would want coliforms to be absent in 100mL and TPC of < 100/mL in treated water (See below).
WHO guidelines describe these parameters the most commonly measured to assess microbial safety:
E. coli: Thermotolerant coliforms may provide a simpler surrogate.
Residual chlorine: Taste does not give a reliable indication of chlorine concentration. Chlorine content should be tested in the field with, for example, a colour comparator, generally used in the range of 0.2–1 mg/litre.
pH: It is necessary to know the pH of water, because more alkaline water requires a longer contact time or a higher free residual chlorine level at the end of the contact time for adequate disinfection.
Turbidity: Turbidity adversely affects the efficiency of disinfection.
Australian guidelines prescribe:
Thermotolerant coliforms (or E. coli) should not be detected in a minimum 100-mL sample of drinking-water.
Colony counts should only be used as an adjunct to routine monitoring for coliforms and thermotolerant coliforms (or alternatively E. coli). When a large number of organisms is detected, some form of remedial action is recommended, such as cleaning storage tanks or inspection and repair of the reticulation system.
The numbers should fall substantially during treatment processes. Generally, colony counts would be as follows in well-maintained supplies (using the Pour Plate technique with Plate Count Agar, at 35-37°C for 48 hours):
Disinfected supply <100 colony-forming units/mL
Undisinfected supply <500 colony-forming units/mL.
Regards,
Tony