In microbiology, "enumeration" is the determination of the number of viable microbes in a sample or drug product. As an analytical testing lab, ChRi uses USP <61> as a benchmark for legal acceptance for testing general microbial contamination of pharmaceutical products. However, to maintain the highest quality control ChRi assess the sample or drug product to assess the proper microbial enumeration technique.
This direct measure for microbial enumeration includes the standard plate count. The sample is diluted, placed on a plate of culture medium, and then incubated. After the sample has incubated for the set amount of time, the number of colonies present is subtracted from the original number of microbes in the sample. This number is not the individual microbes, but rather the "colony forming units" because it's very difficult to determine if each colony came from a single microbe or a tiny group of microbes.
In some instances, direct microscopic or total cell counts are used. The average number of microbes per chamber is determined by counting some or all under a microscope. This number is cross-referenced to calculate the number in the original unit.
Turbidity is the cloudiness of a liquid. A spectrophotometer is used to shine light through the sample in a solution. Then an estimate of the number of living microbes it would take to produce the observed cloudiness level is calculated. Our expertise at ChRi Labs prevents the typical "overly concentrated" sample as a turbidimetric count is only accurate if no microbes in the sample are blocking another.
Microbial Activity Measurement and Mass Determination
Indirect forms of enumeration include both microbial activity measurement. In mass determination, the weight of the biological matter of the sample is compared to a standard curve for known microbial counts. To accurately use a microbial activity measurement, the amount of biological product in your sample is compared to a standard curve for known counts.
The robust expertise and cGMP quality at ChRi Labs recognizes the critical importance of microbial contamination. To accurately provide analytical techniques to determine the specific contamination level, all samples are prepared in a controlled laboratory space. ChRi promises to be an accurate and cost effective solution.