Ph strips

[senorkevin]

Is it important what kind of ph strips I buy? For example, does it matter if the strips are for urine and saliva?

[NCPaul]

Doesn't matter as long as they have the right range.

[wheels]

Paul, how would you prepare the salami sample if using urine strips?

Phil

[NCPaul]

I just tried it with the ones we use at work on a finished salami. I cut a fresh surface and pressed the plastic test strip against the meat; very poor transfer due to low moisture. I took the test strip and wetted it, then patted it dry and then used it; this gave a measurement of pH (as good as the test strips were able to resolve). I can see now the difficulty people have using test papers and I would not recommend them.

[DanMcG]

The strips I have ( which I've yet to use ) recommends mixing a small sample of meat with some water, then test

http://www.butcher-packer.com/index.php ... cts_id=797

[wheels]

I'd appreciate Paul's opinion on that method Dan. Does it need any adjustment for the dilution, etc?

Phil

[NCPaul]

The first thing to remember about pH measurements is that they are on a -log10 scale. Changes in concentration require a correction. As an example, if I dilute my sample by half with deionized water and measure the pH as 5.0, the pH corrected for dilution would be 4.7. If I dilute my sample with three parts of deionized water to one part of meat and measure the pH as 5.0, the pH corrected for dilution would be 4.4. These are just approximations. A better calculation would use the pKa of lactic acid and solve with a quadratic equation (hint, my way is simpler).

[wheels]

Thanks Paul,

That set me thinking, so I had a delve around the net and found this calculator:

http://rechneronline.de/chemie-rechner/ph-dilution.php

I hope this helps Senorkevin

Phil

[DanMcG]

Cool Phil, Thanks for the link!
and thank you Paul for the education...........again.

[senorkevin]

That looks great. Thanks guys. The down side of me using the strips is that I'm colour blind
I was thinking of getting strips that range from 3.9-5.7 and 4.9-6.9
If you wouldn't recommend the strips that what would you?