Reviewed and Approved by Alex Brandt, PhD, Chief Science Officer, Certified Group; Ryan Welsh, M.S., Corporate Operations Support, Certified Group
Your environmental monitoring program (EMP) is only as effective as the data it produces based on your environmental swabbing practices.
To help food safety and quality assurance personnel maximize EMP effectiveness and food safety, we’ve compiled the following list of best practices for environmental sampling.
1. Use the Appropriate Swabbing Tool
- Sponges are ideal for large areas, such as food processing equipment and environmental surfaces.
- Cotton-tip swabs are best for narrow spaces like cracks, crevices, or hard-to-reach areas.
2. Swabbing Technique
- On flat surfaces, use at least ten vertical strokes, ten horizontal strokes, and ten diagonal strokes, while rotating the swab or sponge to cover the entire area.
- Use a systematic pattern (e.g., zig-zag) to maximize recovery of microorganisms from the sampling site.
3. Ensure Adequate Area Coverage
- Swab a sufficiently large area for each sampling site to ensure representative data. A 4”x4” (10×10 cm) area is common for small surfaces.
- For larger areas, swabbing a 12”x12” (30×30 cm) area with a sponge ensures more comprehensive sample collection.
4. Incorporate Neutralizing Agents
- Use a swab or sponge that contains a neutralizing agent to prevent residual disinfectants from continuing to kill bacteria during transport to the lab.
- Choose a neutralizer that is effective against the sanitizers used in your facility and that does not interfere with the analytical assay used.
5. Identify Critical Areas to Swab
- Focus on biofilm-prone areas – target anything sticky, gunky, or that appears to harbor residue, as these are potential biofilm sites.
- Pay attention to surfaces where water and/or food residue lingers (e.g., hollow rollers, crevices, hinges), as these areas are high-risk for harboring microorganisms.
6. Proper Handling During Sampling
- Change gloves between samples to prevent crosscontamination.
- Keep swabs or sponges in their sterile packaging until immediately before use.
- Avoid touching the swabbed area with hands or other surfaces before it is sealed in the transport medium to maintain sample integrity.
7. Maintain a Clean-to-Dirty Order
- Swab areas in a clean-to-dirty order to reduce the risk of cross-contamination during sampling.
- Begin with areas nearest the product (e.g., Zone 2) before moving to less critical areas (e.g., Zones 3 and 4).
It’s also a good idea to randomize environmental sampling locations to ensure you’re getting a good representation of the entire production area.
Environmental monitoring software, such as emma®, our Environmental Monitoring and Mapping Application, can automate and randomize swabbing locations for you, helping save time and improve your program’s effectiveness.
Contact us if you would like to see how emma® can help automate your EMP or if you need laboratory testing for your EMP.
