Environmental Monitoring Programs

This article is reposted from the Cereal Foods World, July - August 2016, Vol. 61, No. 4. The text was developed by the Food Protection Committee of AACC International.

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. Micro-organisms are generally introduced into the food processing environment through raw materials, pests, air, water, and employees. Various pathogenic microorganisms, such as Escherichia coli O157:H7, Listeria monocytogenes, and Salmonella spp., are common contaminants found in food-handling environments.

To ensure the production of high-quality, safe food products it is critical that the hygienic environment in a food processing facility be maintained and monitored. An environmental monitoring program (EMP) can be used to assess the effectiveness of the overall hygienic practices in a facility and to provide information needed to prevent possible microbial contamination of food products. An @@EMP provides valuable data@@ (source and concentration) on indicator organisms, spoilage organisms, and pathogens of concern in a timely manner. An EMP is not designed to validate the effectiveness of cleaning and sanitizing methods; the focus is more on validating cleaning and sanitizing frequencies and other Good Manufacturing Practices (21 CFR 110). The objective of this article is to provide insight into how an effective EMP can be implemented in a food-handling facility to reduce the risk of microbial contamination of finished products.

Why Is an EMP Needed?

It is the responsibility of every food manufacturer to develop and implement an effective food safety program that is capable of detecting signs of microbial contaminants as early as possible and to initiate appropriate corrective actions. These corrective actions must eliminate or reduce microbial contaminants to assure the safety of the finished product. Food Safety Modernization Act: Product Testing and Environmental Monitoring. According to the 2011 FDA Food Safety Modernization Act (FSMA) Preventive Controls for Human Food rule, a facility, as appropriate to the facility, the food, and the nature of the preventive control, must conduct “scientifically valid” environmental monitoring and product testing if:

  • A ready-to-eat (RTE) food product is exposed to the environment before it is packaged
  • The packaged food does not receive a treatment (e.g., kill step) that would significantly minimize environmental pathogens that could contaminate the food

An EMP involves collecting swab samples from food-contact and nonfood-contact surfaces, whereas product testing can occur at the raw material or ingredient stage and/or at the finished product stage. Consequently, environmental monitoring and product testing are verification activities, not preventive controls. However, based on microbial risk assessment and hazard analysis, some facilities may conclude that product testing and/or environmental monitoring are not essential. FSMA also requires written procedures for product testing, environmental monitoring, corrective actions taken to address the presence of a pathogen or appropriate indicator organism in finished food products detected as a result of product testing, and corresponding documentation.

Designing and Implementing an EMP

Different types of food processing facilities (e.g., plant versus animal products, dry versus wet processing, etc.) handling different food products may require different EMPs. There is no universal EMP that can be used effectively in all food processing facilities. The design of an effective EMP is specific to the individual food facility and to the individual operations within the facility. A tailored EMP with a baseline/target will be more effective in assessing the overall sanitary conditions of a specific facility.

Key Components of an EMP

An EMP should be carefully designed after evaluating a facility and its products. Some key components that should be included in a program are:

  • An environmental monitoring team
  • A zoning concept
  • Sampling procedures
  • Selection of indicator and pathogenic microorganisms
  • Sampling tools
  • Labeling and shipping
  • Baseline/target
  • Trends and corrective actions
  • Documentation and mapping
  • Monitoring


A zone concept should be used when designing sampling procedures and collecting environmental swab samples:

Zone 1: All direct food-contact surfaces in the plant, e.g., blenders, conveyors, utensils, work tables, etc.

Zone 2: Nonfood-contact areas in the plant that are closely adjacent to product-contact surfaces, e.g., equipment framework, maintenance tools, drip shields, housings, etc. In general, these are the areas where environmental contamination is most likely to affect the safety of the product.

Zone 3: Nonfood-contact surfaces that are not close to zone 1 surfaces, e.g., walls, floor, drains, air handling units, etc. If a zone 3 area is contaminated with a pathogen, it could lead to contamination of zone 2 through the actions of humans or movement of machinery.

Zone 4: Areas remote from the product processing areas, e.g., office areas, locker rooms, maintenance room, etc. If zone 4 areas are not maintained in good hygienic condition, it can lead to cross-contamination of other zones.

Indicator Microorganisms

@@Choosing indicator microorganisms based on microbial risk assessment is the first step in developing an effective EMP@@. Indicator microorganisms can be used effectively to assess overall sanitation or any environmental condition that might signal or indicate the potential presence of pathogens that could pose significant health risks to consumers. Indicator microorganisms are representatives of specific pathogens of concern, i.e., indicator microorganisms use nearly the same pH, nutrients, temperature, water, etc. as those of specific pathogens of concern. Additionally, effective indicator microorganisms are nonpathogenic, present in high numbers, and less expensive to enumerate.


An EMP and its target/baseline are unique for each plant and each type of product. The target/baseline also is different for different zones. Because the causes of a positive finding are likely to be plant specific, the corrective action required varies from plant to plant and product to product. It is important to compare the environmental sampling results against a target level/baseline. Any increase in microorganism or pathogen number should be monitored because these results signal a possible deviation in sanitary conditions. An appropriate corrective action (e.g., change in sanitizers, change in sanitizing frequency, etc.) should be initiated to bring the values close to or below the target level/baseline.

Positive Results and Corrective Actions

When positive results are obtained, the EMP team should be assembled, and a root cause investigation should be initiated. The area should be thoroughly examined, both visually and through vector swabbing, and the findings should be used to improve operations, such as:

  • Increase cleaning and/or sanitation frequencies or modify methods used
  • Re-examine employee traffic patterns and redirect, if feasible
  • Make repairs (e.g., leaks, cracks, etc.)
  • Audit production handling practices (e.g., product and material handling, etc.)
  • Redesign and/or perform equipment maintenance as needed to eliminate harborage niches that may act as sources of contamination and to facilitate cleaning access
  • Conduct indirect cleaning, such as floor scrubbing and sanitation or cleaning of overhead equipment, A/C ducts and pipes, etc.
  • Increase vector swab frequency
  • Verify effectiveness of processes
  • Document
  • Monitor

Key Benefits of an EMP

An effective EMP:

  • Measures the overall effectiveness of sanitary designs, personnel practices, and operational methods
  • Provides information (source and concentration) on indicator organisms, spoilage organisms, and pathogens of concern in a timely manner so appropriate corrective actions can be initiated to prevent potential microbial outbreaks
  • Is an integral component of a prerequisite program and acts as an early warning system for microbiological hazards in both production and postproduction environments
  • Helps identify microbial harborage niches and hot spots in a plant that may act as sources of contamination
  • Validates the sanitation program and helps in determining the frequencies required for cleaning and sanitation


In recent years, it has become increasingly critical for food processors to implement an effective hazard control program as both the U.S. Department of Agriculture (USDA) and Food Drug Administration (FDA) have become more aggressive in implementing risk-based preventive control procedures. Apart from the food-contact and nonfood-contact surfaces discussed earlier, air, water, and plant employees can also be potential sources of contamination. Thus, periodic swab samples should be collected from the air, water, and plant employee hands and monitored for indicator microorganisms as well as pathogens. When developing an EMP, post-processing environmental monitoring should always be considered, because these are likely areas where pathogens can reappear and recontaminate post-processed food products.

Having an EMP does not guarantee food safety. However, it will provide critical information needed to initiate appropriate corrective actions for preventing contamination of finished products by microbial hazards.

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1 Prepared by Lakshmikantha Channaiah in collaboration with Curtis E. Anderson, Andreia Bianchini, Tom H. Black, Gina M. Clapper, Ellen B. Gay, Janice M. Levenhagen, and Yan Li.

2 Corresponding author: Lakshmikantha Channaiah; Email: lchannaiah@aibonline.org

© 2016 AACC International, Inc.

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