Making 2% skimmed milk in PBS

[Jan Hoolwerf]

Hello,

lpss at unixg.ubc.ca (Alex Chang) wrote:

 AC> I am trying to make 2% skimmed milk in PBS for blocking during my
 AC> panning procedures.

That should be possible. As far as i know some manufacturers sell a product
that is made from skimmed milk but purified in some way.

 AC> I am wondering how to make it sterile.

Is that necessary? Don't think so. Make the solution fresh before use from a
good quality milk powder and i doubt you will have problems with growth of
bacteria.

We produce a skimmed milk powder for a test procedure in the dairy industry and
milk from this powder is used without sterilisation and at 30 øC for six hours.

 AC> I know you can autoclave it. I did it last time, the bottle returned
 AC> to me with brown solutions, I guess it was overdone.

Not overdone, it's the Maillard reaction. Protein with the lactose.

As an alternative you can pasteurize it 15 min. at 100 øC. But it still will be
light brown.

 AC> I also tried filtration using 0.2 um filters, but the milk solution
 AC> clogged the filter easily.

I know. You cannot filter milk through such tine holes <s> and milk from powder
is even worse.


with regards, Jan Hoolwerf

******************* these words were mine, all mine !! ********************
 J.D. Hoolwerf
 Neth. Inst. for Dairy Research
 P.O. Box 20                        phone  : 31-318-659511
 6710 BA  Ede                       fax    : 31-318-650400
 the Netherlands                    e-mail : hoolwerf at solair1.inter.nl.net
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