Is there a difference between APC and HPC?
We are starting to test in-house for HPC (water bottling facility), just wondering if using APC methods would give the same results. Looking to use a rapid / 3M petrifilm type of method. Anyone with experience related to this?
We are starting to test in-house for HPC (water bottling facility), just wondering if using APC methods would give the same results. Looking to use a rapid / 3M petrifilm type of method. Anyone with experience related to this?
Hi lekrueger,
Terminology-wise, apparently no difference. Method/Results-wise, I guess it depends on the methods. Such counts typically have substantial "scatter".
In the field of water microbiology, the aerobic plate count (which is the name often used in food microbiology) used to be called the “standard plate count” and is now called the “heterotrophic plate count” (HPC). It’s pretty much all the same thing: aerobic means that the bacteria had access to air (oxygen) and heterotrophic means that the medium had complex nutrients in it. “Standard” meant that the test was done with the official medium, under official conditions. Obviously, heterotrophic sounds much more official than standard or aerobic.
Dear Lekrueger
As stated by Charles; both HPC and APC are referred generally as STANDARD PLATE COUNT method.
If your starting testing in house for water bottling facility, start through the conventional APC method , gather some data and then validate it with 3M petrifilm technology in contrast; then conclude yourself which method you find feasible and appropriate.
We plate our point of use water on Charm Peel Plates (very similar technology to 3M Petrifilm). The APC plate for water works for us. We sent split sample to third-party lab for validation and results were quite close.
We plate our point of use water on Charm Peel Plates (very similar technology to 3M Petrifilm). The APC plate for water works for us. We sent split sample to third-party lab for validation and results were quite close.
Hi Ryan,
It all depends what you mean by "quite close". And the level.
If the absolute level was <10 cfu/g, +/- 50-100% would be not particularly remarkable even on duplicate plates IMO.
Hi Ryan,
It all depends what you mean by "quite close". And the level.
If the absolute level was <10 cfu/g, +/- 50-100% would be not particularly remarkable even on duplicate plates IMO.
Hi Ryan,
It all depends what you mean by "quite close". And the level.
If the absolute level was <10 cfu/g, +/- 50-100% would be not particularly remarkable even on duplicate plates IMO.
True. Our average count 150 CFU/mL with a standard deviation 26.8 CFU/mL. For micro plating, split samples, between three technicians and an outside laboratory that is quite close.
Hi Ryan,
Assuming 3 samples from same source, this suggests a 95% CI of approx 150 +/- 76%
OK results but not exactly close IMO. But not remarkably different either.
Thanks to all for your input!
Would anyone mind sharing their bottled water sampling plans?
We are producing a high pH alkaline water. current micro testing plan is at startup, every 4 hours, and shutdown (typical continuous 5 day runs): HPC, Total Coliform, E.Coli, Yeast & Mold. Considering adding pseud to the lineup. We have historically never seen a count on Y&M under current testing practices, however get some holds and complaints around the 3-4 month shelf life mark so current testing is not proving to be very valuable.
Any input is greatly appreciated!
Thanks to all for your input!
Would anyone mind sharing their bottled water sampling plans?
We are producing a high pH alkaline water. current micro testing plan is at startup, every 4 hours, and shutdown (typical continuous 5 day runs): HPC, Total Coliform, E.Coli, Yeast & Mold. Considering adding pseud to the lineup. We have historically never seen a count on Y&M under current testing practices, however get some holds and complaints around the 3-4 month shelf life mark so current testing is not proving to be very valuable.
Any input is greatly appreciated!
Hi LEKrueger,
Have you tried Accelerated Keeping Quality - Incubating bottles for up to 7 days then inspecting/testing?
It is particularly useful for detecting low levels of contamination.
Kind regards,
Tony
Thanks to all for your input!
Would anyone mind sharing their bottled water sampling plans?
We are producing a high pH alkaline water. current micro testing plan is at startup, every 4 hours, and shutdown (typical continuous 5 day runs): HPC, Total Coliform, E.Coli, Yeast & Mold. Considering adding pseud to the lineup. We have historically never seen a count on Y&M under current testing practices, however get some holds and complaints around the 3-4 month shelf life mark so current testing is not proving to be very valuable.
Any input is greatly appreciated!
hi leKrueger,
It may relate to things like -
(a) the standard/limits and actual results.
(b) who is complaining/their usage
(c) whether your/user's sampling/analysis methodologies are valid and "equivalent".
Micro data is notorious for generating arguments. Often due to sampling/analytical/calculative methods. But not always.