Challenge test, microbiological

The heating regimen is developed using a KAYE validator or equivalent and copper-constantan thermocouples. The determination of the load cold spot is achieved by actual experiments. A microbiological challenge test was performed to verify the sterilization conditions. Biological indicators... 

The integrity of the product container/closure is assessed by physical tests or microbiological challenge tests and long-term product sterility tests. These tests are specific for container size, fill volume, and closure type. All integrity tests are performed after sterilization and are defined in manufacturing site SOPs. 

Seven thermocouples will be positioned in different locations of the vessel along with one B. stearothermophilus strip (population 10 ) for microbiological challenge test (for thermocouples location, refer to attached layout). 

All parameters during SIP cycle, heat distribution, and microbiological challenge test are meeting the acceptance criteria. 

For rubber stopper requalification, three satisfactory heat penetration studies were performed including a microbiological challenge test. The results of three runs met the acceptance criteria of exposure time, exposure temperature, minimum lethality, and microbiological test. See Table 3. 

Gas niters may be evaluated prior to use by the same methods used for liquid filters (see Section 111 below), allowing that they can be effectively dried out and sterilized without loss of the qualities being tested. Alternatively they may be evaluated by exposure to particles in a gas stream, for instance by the sodium name test, which is also used for HEPA filters. Microbiological tests have to be considered in a somewhat different light. Leahy and Gabler 71 describe an aerosol challenge test of 10 Ps. diminuta bacteria per mL over a four-day period as an appropriate manufacturer s validation test. It would not be practical for routine use. 

B. Microbiological Aerosol Challenge Tests in. Physical Evaluation of Maintenance of Sterility... 

A rigorous approach to microbiological immersion challenge testing is depicted in Fig. 1. This method uses Pseudomonas diminuta grown in Lactose Broth at 3 rc for 24 h. The culture is then sonicated before use to break up any microcolonies or rosettes that may have arisen and that may reduce the potential for this microorganism to penetrate across tiny flaws in intended microbial barriers. 

Microbiological approaches such as that described above are very evidently laborious, time-consuming, and unsuited to routine use. Dye penetration may be substituted for microbiological immersion challenge testing in routine use. 

Glycerol 85 % is a less potent preservative than propylene glycol. It acts as a preservative above 30 %. In lower concentrations it is less effective. Microbiological challenge tests of a zinc oxide cutaneous suspension for example showed an insufficient effect in a concentration of 110 mg/g Glycerol 85 %. Therefore it was replaced with propylene... 

To evaluate the effectiveness of a preservative, it is essential to test finished formulas. There is no standard for preservative challenge testing, but several different test designs can be used to demonstrate the microbiological stability of a product s preservation system. 

DIERCKENS, K., REKECKI, A., LAUREAU, S., SORGELOOS, P., BOON, N., VAN DEN BROECK, W., and BOSSIER, p. (2009) Development of a bacterial challenge test for gnotobiotic sea bass (Dicentrarchus labrax) larvae. Environmental Microbiology 11 526-533. 

---