I'd also recommend trying to autoclave the skim milk solution at only
115 C or even dropping the time to 12 minutes. I prepare skim milk
solutions regularly for use as a cryopreservative. 121 C for 15 minutes
is too much heat for the skim milk.
Marty Gross
Media Preparation
American Type Culture Collection
In article <A138892BF68DD111B45800600842D1E40110B9 at PERRITTLAB01>,
Rfriedel at perrittlab.com (Robert Friedel) wrote:
> 1) Skim Milk Agar- pH 7.0 +/- 0.1
>> Agar 15.0 grams
> Pancreatic Digest of Casein 5.0 grams
> Yeast Extract 2.5 grams
> Glucose 1.0 grams
> Add components except Skim Milk Solution.
>> 2) Skim Milk Solution 100 milliliters
> Add skim milk solids to purified water and bring volume to 100
> milliliters.
> Mix and autoclave for 15 minutes at 121C/15 psi. Cool to 45-50C.
>> 3) Aseptically add 100 milliliters of cooled Skim Milk Solution to (1).
>> Atlas, R. M.
> Handbook of Microbiological Media, 1993
>> Bob Friedel
> Quality Assurance Manager
> Perritt Laboratories, Inc.
>rfriedel at perrittlab.com>> -----Original Message-----
> From: Hochberg, Alan M [mailto:Hochbeam at Qualicon.email.dupont.com]
> Sent: Thursday, February 22, 2001 7:52 AM
> To: micro-list at qualicon.com> Subject: Microbiology List: FW: MILK agar?
>>> From: J.Rowlands [mailto:oss004 at bangor.ac.uk]
> <mailto:[mailto:oss004 at bangor.ac.uk]>
> Sent: Thursday, February 22, 2001 6:43 AM
> To: microbio at hgmp.mrc.ac.uk <mailto:microbio at hgmp.mrc.ac.uk>
> Subject: MILK agar?
>> G'day all,
>> I've a student trying to get to grips with milk agar for a protease test.
> It's a long time since I did this! References suggest autoclaving
> milk-powder solution, but this seems dooomed to failure with heat
> denaturation.
> Anyone currently engaged successfully in milk agar that can give advice
> will
> become our lab hero for the week!
> Many thanks,
> John Rowlands,
> University of Wales, Bangor.
