How do you weigh a powder...?

Michael Kolotila x3887 mkolotila at
Mon Jan 22 11:03:59 EST 1996

Dear Takashi;
I would suspect that they do not want to wash spatulas or they fear 
cross-contamination with other media components.  Material from any food 
source will contain bacteria.  Plate out ground pepper or hamburger and 
you will find a lot of bacteria.  Powder media goes everywhere even with 
a spatula if you are not careful and makes counter tops sticky when they 
get wet.  

 Michael P. Kolotila, Ph.D.        * e-mail: mkolotila at   
 Biotechnology Program Coordinator *          
 Department of Natural Science     * voice :  508-374-3887
 Northern Essex Community College  *
 100 Elliott Way                   * fax   :  508-374-3723
 Haverhill, MA  01830-2399         *        

On 19 Jan 1996, Takashi Yoshida wrote:

> Hello, people.
> I am working in a laboratory of microbiology in Japan. 
> In this labo, all of the staffs never use a spatula when 
> weighing peptone, yeast extract and other nutrient powders. 
> Instead, they spill the powder onto a paper by gently 
> druming the bottom of bottles (what a skillful method !).
> I don't understand why they never use a sparula for 
> weighing such fine powdered material. When I ask the 
> reason,  they say that they fear a contamination of 
> nutrient bottles by unfavorable microorganisms.  
> But, I fear the fine powder of nutrient will be spread 
> over the room.
> How do you think about it?
> Do you think I am lacking in something fundamental 
> biochemical knowledge? Or, is there any good way?
> -- 
> 吉田 孝 Takashi Yoshida 
> Tohoku University, Sendai, Japan.
> email:  yoshida at 

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