Our lab manager suspect that something wrong with our lab Bacto agar (Difco). So she decide to throw it to the garbage. I think that it's just a waste to throw that thing. Can someone think of reason why don't use that agar for molecular cooking in my kitchen? (My lab manager think that i am totally crazy without give any reason)

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    $\begingroup$ I'm voting to close this question as off-topic because it has nothing to do with either biology or biological techniques. There may be some other SE site (Health, Domestic Science?) where it is appropriate, but that's for the poster to find out. $\endgroup$
    – David
    Commented Jan 15, 2018 at 19:49
  • $\begingroup$ If there are reasons to not use it for lab stuff, maybe there are reasons for not using it for cooking either. $\endgroup$
    – Remi.b
    Commented Jan 16, 2018 at 3:23

1 Answer 1


Technically agar has first been used (and still is) in the kitchen and then adopted to the lab. In the 19th century, gelatin was used in the microbial laboratory. The problem is that gelatin is much less thermostable than agar and at higher cultivation temperatures plates will melt and get liquid again. In 1882 the german microbiologistt Walther Hesse (at that time an assistant in Robert Kochs laboratory) followed the suggestion of his wife Fannie Hesse to use Agar instead of gelatin. See the two references for some interesting details.

I personally would never use anything which comes from the lab in my kitchen since you never know if there are any contaminants in there. This is also probably the reason, why your lab manager doesn't want you to have it.


  1. Walther and Angelina Hesse-Early Contributors to Bacteriology
  2. History of the agar plate
  • $\begingroup$ What kind of contamination should I suspect? We use specific spoon to take out the agar from the box that used only for this. $\endgroup$
    – Moshe
    Commented Jan 15, 2018 at 13:09
  • $\begingroup$ The agar doesn't care where it is prepared, however, I am 100% with Chris on this one, I wouldn't use any coming from the lab for fear of contamination. I don't know what kind of organisms you work with and what you may find in your environment but generally it is not a good idea to mix things that were used in the lab with things that you use in your kitchen. $\endgroup$
    – Johnny
    Commented Jan 15, 2018 at 13:58
  • $\begingroup$ I don't think that I need to worry from the bacteria that I have in my lab more then the normal bacteria that I (probably the same) have in my kitchen. I am more worried if they use something in the production of the Agar that is toxic to people. $\endgroup$
    – Moshe
    Commented Jan 15, 2018 at 15:16
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    $\begingroup$ @Moshe I think more about lab chemicals which are present where agar gels are prepared like Ethidiumbromide. Or people using dirty spoons/spatulas before going into the agar. The agar itself is prepared from algae and my guess (although I don't know for sure) is that the lab agar is pretty clean. $\endgroup$
    – Chris
    Commented Jan 15, 2018 at 15:25
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    $\begingroup$ @Pere In general you are right. But: This is a general precaution to avoid harm. We have a number of substances in the lab that can be nasty. $\endgroup$
    – Chris
    Commented Apr 10, 2019 at 10:15

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