Why
should someone who is using food grade agar to grow cultures switch
to bacteriological grade agar?
Take
care when using food grade agar for bacteriological purposes. Many food
grade agars are produced with gracilaria or gelidiella seaweed's and
the gel strength of food grade agar that's produced is between 300 and
500 gms/cm2. What does that mean?
The
real problem is the gelling temperature of food grade agar, that is
40° - 44° Celsius. High quality bacteriological grade agar MUST be extracted
from selected gelidium sesquipedalis seaweed's (not gracilaria or gelidiella
seaweed's). This requirement gives bacteriological grade agar a gelling
temperature of 34° - 35.5 Celsius.
Agar
is a colloidal substance, it is insoluble in cold water, but soluble
in boiling water. When cooled to 34° - 43°C, it forms a firm gel which
does not melt again below 85°C.
Our
bacteriological grade agar has gel strength of 920 gms/cm2
Important
Factors for Bacteriological Grade Agar
- gel
strength that must be over 800 gr/cm2
- transparencies
must be lower than 10 NTU but top qualities agar are even lower
than 5 NTU
- divalent
captions that must not be higher than 1.000 PP
To view
The Certificate of Analysis for our Bacteriological Grade Agar, please
click
here
For
reference and recipies on how to use bacteriological grade base agar,
please visit The
Sporeworks for an easy and successful way to prepare
this media.
