Help ! The color of Blood agar plate.

Dilworth bactitech at
Wed Nov 15 23:22:01 EST 2000

Ours are a nice bright red when we get them from the manufacturer.  Have they

been subjected to high heat somewhere in shipping?  This will effect the
appearance of the media.  Likewise, in cold weather, freezing will hemolyze
the red cells.

Are you quality controlling the media when you receive it to make sure it
supports the growth of basic pathogens such as Staph. aureus, E. coli, Group
A beta streptococci, Streptococcus pneumoniae?  If these all grow and look
right, then your media is probably okay.

I would think that all media you are receiving from such a long distance away

should be quality controlled with known pathogens to test for viability,
especially chocolate agar and selective media such as Thayer Martin for
pathogenic Neisseria species, and any media with antibiotics in it such as

Judy Dilworth, M.T. (ASCP)

Simon Lee wrote:

> Is there any one who know the method that improve Blood agar plate ?
> Because of low PaO2 of sheep blood, our blood agar plate appears slightly
> dark red. - import from USA to south Korea. -
> The method which I have done is addition of O2 or CO2 into sheep blood.
> But it is not satisfactory.
> Please let me know the way ASAP.

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