Microbial challenge

Algal chemical defenses that inhibit the settlement and attachment of pathogens or biofoulers represent the first line of defense against microbial challenge. Unlike compounds that function through growth inhibition or lethality, most settlement and... 

The selection of the preservative system for multiuse new products is the responsibility of the R D formulation group. Typical shelf specifications are 80 to 120% of label specifications. The appropriate preservative system for the particular formulation should be demonstrated to be effective by microbial challenge to at least 75% and preferably 50% of the target concentration. It is recommended that during development the product be formulated with preservative concentrations of 100, 75, and 50% of the labeled amount and be subjected to antimicrobial effectiveness testing to determine the lowest effective preservative concentration. 

At least one set of microbial challenge or penetration test containers shall be placed in the sterilizer cold zone per run (where applicable). 

A minimum microbial challenge spore log reduction of equal to or greater than six must be shown for each mn. 

Copies of all microbial challenge protocols, which should include identification of the types, crop numbers, and D values for the biological indicators used... 

All finished products are tested for sterility in a controlled-access clean room environment in a laminar flow hood, which provides no greater level of a microbial challenge than that encountered in the fill environment. The testing environment consists of a gowning room and sterility test suite that meets the same air quality standards as the hlling suite. 

The sterile solutions are filled in different sizes of ampoules/vials under aseptic conditions. For this purpose, all operations and conditions require validation according to the approved protocols and subsequent requalification on an annual basis by one heat penetration study and microbial challenge test using a B. stearothermophilus strip. 

Sterilization cycle one heat penetration study and microbial challenge test using B. stearothermophilus strip... 

Microbial challenge test Minimum 6 spore log reduction ... 

Prior to microbial challenge testing of the tunnel sterilization, heat-penetration studies must be completed in order to identify the coolest container in the entire load. Results of heat-distribution studies should aid in predicting where the coolest location within the load should be. Thermocouples should be deposited at or near the coolest point inside the container as determined previously from bottlemapping studies. Normally, the coolest point inside the container is at the juncture of the bottom of the container and the sidewall. The container s inner surface should be in contact with the thermocouple tip because the objective is to sterilize the inner walls of the container, as well as the inner space. 

With both micro-organism and endotoxin challenges, the cool spot identified in the heat-distribution and heat-penetration studies will be the logical location to run the microbial challenge tests. Containers inoculated with microbial cells or endotoxin will be situated adjacent to identical containers into which thermocouples are secured to monitor temperature. Temperature profiles must not deviate from temperature data obtained in earlier studies. 

The microbial challenge test can be performed on a particular filtration medium, whether disk or cartridge type, by following these general steps ... 

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