Single Temperature Analysis for Environmental Monitoring Samples

This content was first published by European Pharmaceutical Review (EPR).

Author: Marion Louis, bioMérieux

Determination of the feasibility and the impact of the single temperature for environmental monitoring microorganisms

ENVIRONMENTAL MONITORING (EM) is one of the main microbiological controls that pharmaceutical industries perform to ensure the safety and efficacy of pharmaceutical products. To efficiently control the quality of these products, the presence of potential microbial contaminants must be monitored. Although the traditional method is extremely manual, variable and error-prone, it remains the standard procedure used in industry for hundreds of millions of samples per year. While the level of requirements in data integrity and data traceability is increasing from regulations and inspections, pharma manufacturers are simultaneously willing to improve process efficiency and productivity thanks to time saving and deviation reduction. This enables traditional methods and practices to be questioned, such as the incubation period for EM samples.

Dual or single temperature?

Regulations for environmental monitoring provide wide guidance on temperatures and regime to follow1-4 and to avoid any risk of missing a microorganism, it has been commonly adopted by pharmaceutical industries for several years that two sequential temperatures (usually 20-25°C, followed by 30-35°C) would match the main flora encountered. And indeed, a survey5 from the Parenteral Drug Association (PDA) in 2017 revealed that 73 percent of polled pharmaceutical companies chose dual temperature incubation as their most common practice.

This incubation regime, defined a couple decades ago, is not questioned nor revalidated on a regular basis while the flora can evolve with a risk that some new microorganisms can be not detected during the EM campaign. Besides, today, more and more industries are considering adopting single temperature for environmental monitoring samples, as 70.8 percent of respondents currently using dual temperature are open to adopting single temperature6 as it brings valuable benefits.

Processing single temperature decreases manual handlings of the samples during the transfers of incubators and manual transcription; therefore decreasing mistakes and related investigations.

Recent studies from several companies7 have indeed determined that single temperature is at least equivalent or better to detect the flora they have. They also underlined that regardless of the final choice, the key aim is to ensure that it fits with the flora in place. Indeed, each microorganism has its own growth criteria in terms of culture media components, incubation temperature and time. Such optimal growth conditions linked to each microorganism's specificity are difficult to be conducted during EM and consensus may be made to find the good balance for the existing flora.