Reference microorganism used for Growth Promotion Test for Sterility testing media.

Sterility testing is one of the most important and critical testing in microbiology. It is a method by which we check the viable contamination in sterile items. In pharmaceuticals, sterility testing is performed to check viable contamination in sterile drugs like Liquid injections, Dry injections, SVP, LVP etc. In sterility testing basically two media are used.

(1) Soyabean casein digest medium (SCDM) used to detect aerobic bacteria and fungus.

(2) Fluid  thioglycollate medium (FTM) used to detect aerobic, facultative and anaerobic bacteria.

Sterility is one of the important parameter of release of any sterile product into the market. So, sterile product must pass the sterility testing before its release into the market. Growth promotion test is very important and in pharmacopoeia different microorganisms are mentioned for the growth promotion test of sterility testing media. List of microorganisms is mentioned below.

Microorganisms used for Growth Promotion Test of Sterility testing media

Medium	Test Microorganism	Incubation
		Temperature (°C)	Duration	Type of Microorganism
FTM	Clostridium sporogenes (ATCC' 19404)	30-35	3 days	Anaerobic
	Staphylococcus aureus (ATCC 6538)	30-35	3 days	Aerobic
	Pseudomonas aeruginosa (ATCC 9027)	30-35	3 days	Aerobic
SCDM	Aspergillus brasiliensis (ATCC 16404)	20-25	5 days	Aerobic (Mold)
	Candida albicans (ATCC 10231)	20-25	5 days	Aerobic (Yeast)
	Bacillius subtilis (ATCC 6633)	30-35	3 days	Aerobic

Inoculate a portion of Fluid Thioglycollate Medium with a small number (not more than 100 cfu) of the following microorganisms, using a separate portion of medium for each of the following species of microorganism: Clostridium sporogenes, Pseudomonas aeruginosa, and Staphylococcus aureus.

Inoculate portion of Soybean–Casein Digest Medium with a small number (not more than 100 cfu) of the following microorganisms, using a separate portion of medium for each of the following species of microorganism: Aspergillus brasiliensis, Bacillus subtilis, and Candida albicans. We can use ATCC or equivalent strains for growth promotion test.

Form the above statement it is clear that we have to use each of the above mentioned microorganisms for the GPT. Incubation time is not more than 3 days in case of bacteria and not more than 5 days for fungus which means if copious growth found in the media before 3 days or 5 days then we can remove that media form the incubator and note down the observation. Each autoclaved load of each lot of the medium should be tested for the GPT. The media are suitable if clear and copious growth of the microorganisms occurs.

Thanks!