Recovery balance: a method for estimating losses in a Bacillus anthracis spore sampling protocol

Area of Science:

• Microbiology
• Analytical Chemistry
• Surface Science

Background:

• Microbial surface sampling is crucial for hygiene monitoring.
• Existing protocols often lack detailed performance assessment.
• Understanding error sources is key to improving sampling accuracy.

Purpose of the Study:

• To develop a quantitative method for assessing microbial surface sampling performance.
• To identify and quantify error contributions within a sampling protocol.
• To establish a framework for optimizing microbial wipe sampling.

Main Methods:

• A slip/peel tester ensured consistent pressure during wipe collection.
• Fluorescence microscopy quantified deposited spores.
• A recovery balance (RB) method, analogous to mass balance, estimated efficiency at each step.
• Two studies validated the RB method and assessed parameter impacts.

Main Results:

• The recovery balance (RB) method successfully quantified performance.
• Significant spore loss to the wipe material was observed (39.9%).
• The method demonstrated applicability in evaluating factors like humidity and wipe material.

Conclusions:

• The recovery balance (RB) method provides a robust approach for analyzing microbial sampling protocols.
• Substantial spore loss to wipes necessitates further investigation into spore-wipe interactions.
• This method aids in optimizing laboratory-based sampling protocols and developing new methodologies.