Old days separate media plates were used for bacteria and fungal
count.
SCDA –support the growth of both fungal and bacterial therefore
single plate used for both.
Time saving and cost effective approach.
Fungal – (Yeast & Molds) can grow at 22.5 ± 2.50C
for 3 days (72 hours)
Bacterial - can grow at 32.5 ± 2.50C for 2days (48
hours) respectively.
But USP -1116 general chapter we can incubate the same plate first
at 32.5 ± 2.50C for 2 days (48 hours) and then 22.5 ± 2.50C
for 3 days (72 hours) . this was revised in 2012.
If the lower temperature is selected first to incubate the
plate.
Then the growth of gram positive cocci (slow growing) and
mesophilic bacteria may be affected.
These are associated with human generated contamination.
So their recovery is important.
Incubation
first at 22.5 ± 2.50C for 3days (72 hours) and 32.5 ± 2.50C
for 2 days (48 hours).
SCDA
- Soybean
Casein digest Agar(Tryptic Soy Agar)
- Used for cultivation of wide variety of micro organisms and for sterility testing in pharmaceutical procedure.
- Highly neutrent medium
Composition Gram / Liters
Pancreatic digest of
casein(Casein peptone) (peptone C) ----- 15.000
Papaic digest of
soyabean meal(soy peptone) or (peptone S2) --- 5.000
Sodium chloride
---------------------------------------
5.000
Agar----------------------------------------------------
15.000
pH = 7.3 ± 0.2
at 250C
- Pancreatic
digest of casein (peptone C) and papaic digist of soy bean meal (peptone
S2) source of amino acid growing
of microorganisum.
- Sodium
chloride- osmotic balance
- Agar----solidifying
agent.
