How to Use a Sampling Swab for Surface Monitoring

Surface monitoring using sampling swabs method is best to evaluate the effectiveness of hygiene procedures on uneven surfaces. The following describes the steps for surface monitoring using the swab method:

• The sampling swab is dipped into 5 ml neutralizer or broth medium and rubbed against the selected test area. The swab is returned into the test tube containing neutralizer or broth medium.
• Approximately 1 ml of the medium is acquired and plated onto a petri dish.
• Desired agar is added for the enumeration of microorganism. Agar is added with TSA to evaluate bacterial presence or SDA to evaluate the presence of yeast and mould.
• In instances where a sample is collected right after disinfection, appropriate neutralizer can be added to the broth if disinfectant residue is suspected.
• The medium can also be diluted if sample is expected to contain high amounts of microbial load. Incubate bacteria for 2 days at 37°C and yeast and mould for 3 days at 30°C.
• The swab method is suitable for small areas and areas with cracks and crevices. Swabs can cover larger areas compared to contact plates. The downside of using this method is that microorganism might reduce or increase in the neutralizer or broth medium (depending on the media) if the time between sampling and plating is too long.