Environmental Monitoring | American Society of Baking
Food Safety:

Environmental Monitoring

What is environmental monitoring?

Environmental monitoring (EM) is a planned sequence of samplings, observations, and measurements used to evaluate the effectiveness of microbiological agents in food processing facilities.1

EM is a key prerequisite program (PRP) that determines whether or not cleaning and sanitation procedures and frequencies are effective.2

The scope of EM covers all areas of a facility. As a PRP, EM supports the implementation of food safety management systems such as HACCP, HARPC, and others.

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Microorganisms are generally introduced into the food processing environment through raw materials, pests, water and air supply, cross-contamination with external sources, and employees. Pathogenic microorganisms, such as Escherichia coli O157:H7, Listeria monocytogenes, and Salmonella spp., are common contaminants found in food processing environments.3

Despite advances in food safety, foodborne illness outbreaks remain common occurrences around the globe. Foodborne illnesses affect millions of people and cause thousands of fatalities every year. A substantial number of these outbreaks result from poor environmental controls and/or hygiene practices.3

EM is an important program for food plants, especially those that handle microbiologically sensitive foods. With the recent regulatory focus on identifying and controlling food hazards, more and more food facilities are establishing and improving their environmental monitoring programs.3

Regulatory compliance4

Preventive controls identified in the hazard evaluation stage need appropriate verification activities. This includes environmental monitoring to verify effectiveness of those controls for pathogens or appropriate indicator organisms.

Under 21 CFR Part 117 Subpart C Section 130 (2), the EM evaluation must consider the following issues, which affect food safety for the intended consumer:

  • Food formulation
  • Condition, function, and design of the facility and equipment
  • Raw materials and other ingredients
  • Transportation practices
  • Manufacturing/processing procedures
  • Packaging and labeling activities
  • Storage and distribution
  • Intended or reasonably foreseeable use
  • Sanitation, including employee hygiene
  • Temporal (e.g., weather-related) factors that can affect the nature of some hazards (e.g., level of toxins)

Application and scope of EM

What should be tested?

There are three categories of organisms that can be included in EM:

  1. Pathogens: It is important to test for the pathogens of relevance to your type of operation, e.g., Listeria monocytogenes, Salmonella, E. coli, Campylobacter, Staphylococcus aureus, Bacillus cereus, etc. The test for pathogens simply reveals whether they are present or absent; enumeration is not necessary.
  2. Spoilage organisms: Yeast and mold are the most concerning spoilage organisms that food facilities should include in their environmental monitoring programs. The most common molds are Aspergillus, Fusarium, Penicillium, and Alternaria. Air and surface testing are equally important in identifying the presence of these organisms.
  3. Indicator organisms: These are a basic monitoring tool used to measure the potential presence of hard-to-detect pathogenic organisms, e.g., Coliforms, Enterobacteriaceae, and Aerobic Plate Count (APC).5

Where should you test?5

Zone 1: Direct product-contact surfaces Zone 2: Non food-contact areas closely adjacent to Zone 1 Zone 3: Non food-contact surfaces that are not close to Zone 1 Zone 4: Areas remote from the product processing areas
Processing equipment (e.g., mixers, ovens); utensils, work tables, conveyors, storage silos, and bulk containers Equipment framework, aprons, tables, maintenance tools, housings, ancillary equipment (e.g., compressors, heat exchangers, pumps) Walls, ceilings, floors, drains, sinks, handling units (e.g., forklifts) Office areas, locker rooms, warehousing, sanitation wash rooms, overhead doors, racks
  • Little or no testing should be done in Zone 1. If pathogens are found in Zone 1, it is likely a recall situation and it is too late.
  • Sampling should focus on high-risk areas, such as Zone 2, which has greater access to the product, and areas with wet and warm conditions that encourage bacterial growth.
  • If Zone 4 areas are not maintained in good hygienic condition, this can lead to cross-contamination of other zones.

How can you accomplish this?

  • It is valuable for food facilities to have a microbiologist on staff. Such a person may contribute a solid science background and/or prior experience in environmental monitoring.
  • Sampling swabs and sponges, air-sampling devices, and ATP bioluminescence assay kits are some options available that are vital for a correct site sampling.
  • Mapping of all sampling locations should identify each area, and the specific zones within each area, that will be tested. This can be an effective way to identify hot spots that require appropriate corrective actions.
  • Mapping locations of conforming (negative) results, increasing trends, and nonconforming (positive) samples/results on a facility design diagram can help define the scope of the problem.

Steps to build an EM Program (EMP)5

  • Create the EMP team
  • Apply the 4-Zone concept
  • Define microbiological indicators
  • Set sampling frequencies
  • Set appropriate labeling and shipping procedures for swab samples for in-house analysis and external laboratory analysis
  • Establish a result baseline/target
  • Test surfaces
  • Implement corrective action for nonconforming results
  • Verify written EM procedures
  • Keep records


  1.  AIB International. “Food Safety and Sanitation.” Food Safety and Sanitation Distance Learning Course, Chapter 17.
  2.  Ryan, J.M. “In-transit Container Sanitation Standards: Packaging and Control of Packaging.” Guide to Food Safety and Quality During Transportation: Controls, Standards and Practices, 2nd ed., Elsevier Inc., 2017, pp. 197–222.
  3.   AIB International. “Environmental Monitoring Programs.” 2016, http://foodfirst.aibonline.org/foodfirst/2016/9/20/environmental-monitoring-programs?rq=microbial%20control
  4.  U.S. Food and Drug Administration. “21 CFR 117 – Current Good Manufacturing Practice, Hazard Analysis, and Risk–based Preventive Controls for Human Food.” 1 Apr. 2017, https://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfcfr/CFRSearch.cfm?fr=117.130
  5. AIB International. “General Guidance for Establishing an Environmental Monitoring Program.” 2015, http://foodfirst.aibonline.org/foodfirst/2015/6/4/general-guidance-for-establishing-an-environmental-monitoring-program?rq=microbial%20control