12 Essential Elements for Pathogen Environmental Monitoring (PEM) in Manufacturing Plants

For any Food Safety Program, preventive controls are crucial for overall success. As regulatory requirements continue to become more stringent, robust prevention in the area of pathogenic environmental monitoring (PEM) is imperative. 

That’s why we’ve put together 12 essential elements for any Pathogen Environmental Monitoring Program. No matter the size of your organization or industry in which you participate in, these principles are must-haves when evaluating a current program or starting a new one from scratch.


1. Conduct an Environmental Risk Assessment

This determines risk areas, niche points, and evaluates traffic patterns and process flows as risks for processes.

2. Create a Plant Map

Mapping out production vs. general use areas as well as equipment locations.

3. Conduct a Hygienic Zone Assessment

This ensures production areas are properly zoned for avoiding cross contamination. 

4. Determine Sample Sites

Based on a risk assessment, high-risk areas can be determined to ensure inclusion in the sampling plans.   

5. Determine Sampling Frequency

Best practice recommends weekly sampling in Zones 2 and 3. Once your sample sites are determined, this step establishes a protocol for the testing of each site. 

6. Evaluate Sampling Materials

Sampling materials must be appropriate for the site.  Sponge vs. swabs as well as the neutralizing buffer and recovery of the target organism should be considered. Polyurethane typically outperforms cellulose materials.

7. Receive Training on How to Properly Collect Environmental Samples

Since techniques for collecting samples in plants varies depending on where the sample is being collected from (drains, walls, floors, liquid vs. dry samples, etc.), receiving training on how to standardize and complete this correctly is essential. Collecting samples properly is the only way to ensure conclusive results for your sampling plan. 

8. Submit Samples to Lab for Testing

Temperature is essential when storing and shipping samples. Correct labeling is also important as well as ensuring sample integrity during shipment. Cooler re-use which isn’t managed, can cause contamination issues.

9. Evaluate Testing Technologies

The types and methods of available testing technologies are numerous. Download our Service Schedule Guide for definitions and time frames concerning testing technologies. 

10. Develop Corrective Action Documentation

Based on the findings of your PEM data, corrective actions may be needed. You’ll want to document the steps being taken and measurable ways to follow up on the progress of monitoring issues moving forward. Corrective action should include consecutive negatives as well as vector sampling. Ensure effective root cause investigation.

11. Incorporate Standard Operating Procedures and Group Training Sessions in Your Program

Most organizations will quickly pinpoint processes that need improvement to address gaps when pathogens are detected in the environment. Standardization and training will help address these gaps.

12. Review, Refine, Revamp

A Food Safety Plan should remain dynamic. Organizations that succeed embrace ongoing modifications and refinements.

These are 12 components of what can be a complicated, but necessary, process for any organization. Contact Chestnut Labs with any questions about how to assess, design, or implement a Pathogen Environmental Monitoring Program that works.

Bryce Wilks