How to Establish a Pathogen Environmental

Monitoring (PEM) Program By Ivy Cho

ivyc@abcr.com

Questions to ask

• What are the environmental sources of spoilage organisms?

• Where is the presence of foodborne pathogens or their indicators in the environment and on the equipment?

• How effective are the cleaning and sanitation practices?

• How frequent should the cleaning and sanitation be practiced?

Facility environment

• Pathogens can enter as raw materials, ingredients, pests, or by people.– Persist in niches and hot spots and

moves through the facility by traffic flow, dust, and condensation

Perfect recipe for contamination!

Microbiological concerns

• Pathogens– Salmonella spp.– Listeria spp.– E. coli 0157:H7

• Indicator organisms: non-pathogenic, indicators for contamination– Aerobic plate count– Coliforms– E. coli

PEM zoning concept – Zone I

• Zone I: direct or indirect product contact surfaces after the lethality or microbial reduction step and before the product is sealed in the primary package

PEM zoning concept – Zone II

• Zone II: non-product contact sites adjacent to Zone I

PEM zoning concept – Zone III

• Zone III: non-product contact sites adjacent to Zone II, areas of cross-contamination risk

PEM zoning concept – Zone IV

• Zone IV: areas remote from Zone I

PEM zoning concept examples

Zone I – slicers, conveyors, peelers, strip

tables, utensils, work tables, racks, employee hands, pumps, hoppers,

fillers

Zone II – exterior of equipment, refrigeration units, framework,

equipment housing

Zone III – phones, air return covers, hand trucks, forklifts, walls, floors, drains

Zone IV – cafeteria, locker rooms, halls, warehouse, loading dock

Sampling methods for PEM

• The use of proper sampling methods is crucial for ensuring reliable and defensible data.– Surface sampling: sponges and swabs– Product residue scraping and dust

samples–Water and rinse samples– Air samples

Establish your baseline

• Investigational sampling is intensive to establish a baseline.– It is not uncommon to sample

25-50 target areas in each zone everyday for a

month.

• By determining the baseline counts, it will be established what is unacceptable and acceptable under normal operating conditions.

• Move to routine sampling; rotate sites and test each site 4 times a year.

Sampling Diagram

Zone Sampling site Microbiological analyses

Minimum sampling frequency

Number of samples

I Direct product contact site

Indicator organisms and pathogens under

special situations

Weekly Line dependent

II non-product contact sites

adjacent to Zone I

Pathogens Weekly 10-15

III non-product contact sites

adjacent to Zone II, areas of cross-

contamination risk

Pathogens Weekly 10-15

IV areas remote from Zone I

Pathogens Monthly 5-10

How valuable is a PEM program?

• It is more dependable and concrete to monitor the environment than to depend on finished product testing only.– Can help identify and eliminate

harborage niches and hot spots.– Can demonstrate food safety competence

to visitors (auditors, buyers, regulators).– Verifies that sanitation, GMP’s, and pre-

requisite programs are working in competence.

Related information

Video instructions on how to perform environmental sampling

The dos & don'ts of environmental sampling

Video instructions on how to sample water & ice

How to sample for laboratory water testing

Questions?

For additional information, please contact us at 352.372.0436 or visit our website at abcr.com