Food processing and packaging line

Food recalls: How proactive environmental monitoring can help food processors

We see food recalls come across our news feed regularly. The recall may be lettuce, chicken or dog food, but whatever the product, they are costly and potentially harmful to health.

Recent recalls in the food and beverage industry highlight the need for food processing facilities to have proactive and comprehensive environmental monitoring programs. While food manufacturers put heightened emphasis on cleaning and sanitation protocols, the validation and verification of those controls are critically important in preventing an outbreak of a foodborne pathogen. 

As you evaluate your environmental monitoring program as part of your overall food safety plan, here are a few questions you should address, along with some resources to help ensure you are taking a holistic approach.

Food processing surface for environmental monitoring testing

Download a digital copy of the 3M Environmental Monitoring handbook

Do you have a robust environmental monitoring program for Listeria?

Listeria is ubiquitous in the environment, often found in moist conditions, including soil, surface water and decaying vegetation. Listeria monocytogenes is the most infamous of the seventeen known species in the Listeria genus. While it’s not the leading cause of foodborne illness, it is among the leading causes of death from foodborne illness.  The U.S. Centers for Disease Control and Prevention (CDC) estimates that, in the U.S., domestically acquired foodborne L. monocytogenes results in 255 fatalities per year.

Food processors should consider testing for this persistent pathogen, not only by testing finished product, but by sampling food contact and non-food contact surfaces in food production environments that could be reservoirs for Listeria. For key considerations in monitoring your environment for Listeria, download our Environmental Monitoring Handbook, created in partnership with Cornell University and industry experts.

Additionally, incorporating rapid, sensitive and specific pathogen testing into your program can help you quickly identify potential sources of contamination and resolve issues before they impact finished product and consumers. 3M’s pathogen detection platform, the 3M Molecular Detection System, is an FDA accepted method for detecting Listeria species in environmental samples. The USDA has selected it as the primary method to be used for the detection of Listeria monocytogenes.

Additional Resources

U.S. FDA Draft Guidance for Industry: Control of Listeria monocytogenes in Ready-To-Eat Foods

Are you effectively validating and verifying cleaning and sanitation?

There are three established and recognized approaches that can be used for hygiene monitoring: visual inspection, microbiological testing and Adenosine Triphosphate (ATP) testing. A robust hygiene monitoring program should utilize all three complimentary methods.

1. Visual inspection can quickly give a big-picture view about the effectiveness of your cleaning processes. But it has limitations because microorganisms cannot be seen by the naked eye. Also, there may be surfaces on production equipment that cannot be visually inspected but may be contaminated. Visual inspection can still be an effective precursor to microbiological and ATP testing, used together or individually.

2. Microbiological testing can enumerate organisms that may cause food contamination. However, it cannot provide immediate results on the manufacturing floor. Samples must be taken to other locations for processing and analysis or may require days to produce results. During that time food can be held, potentially reducing shelf life and sales, or food can be released but may need to be recalled if contamination is found.

3. ATP testing is a widely accepted method that is highly efficient because it quickly and easily provides results. Instead of enumerating microorganisms, it measures ATP from microorganisms and food residues. This immediately indicates whether cleaning has been effective so manufacturing can begin or shows that re-cleaning and re-testing are necessary to reduce potential contamination before food manufacturing starts.

A complete hygiene monitoring and management system should automatically turn raw data into organized information, enabling immediate identification of trends and problem areas. The baseline data can also be used to establish initial performance guidelines and drive continuous improvement. Using accurate data from a hygiene monitoring and management system will help you determine whether you are meeting the thresholds and standards you have established as part of your environmental monitoring program.

For more information on this three-pronged approach, read this guide on

Hygiene Monitoring’s Role in an Environmental Monitoring Program

Additional Resources

3M™ Clean-Trace™ Suggested Sampling Sites

3M™ Petrifilm™ Plates Environmental Monitoring Procedures

Solutions for Microbiological Testing

3M™ Petrifilm™ Plates

Solutions for ATP Testing

3M™ Clean-Trace™ Hygiene Monitoring and Management System

Are you selecting the right sampling sites?

Sampling site selection should begin with a mapping exercise to give an overview of the complete facility and production process. This includes dividing the facility into several areas or zones based on the microbial risk to the product.  An example of how these zones are typically defined is as follows:

Zone 1: Product Contact Surfaces (Highest Risk)

  • Slicers, peelers, fillers, hoppers, screens, conveyor belts, air blowers, employee hands, knives, racks, work tables

Zone 2: Non-Food Contact Surfaces in Close Proximity to Food and Food Contact Surfaces

  • Processing equipment exterior and framework, refrigeration units, equipment control panels, switches

Zone 3: More Remote Non-Food Contact Surfaces Located in or Near Processing Areas

  • Forklifts, hand trucks, carts, wheels, air return covers, hoses, walls, floors, drains

Zone 4: Non-Food Contact Surfaces Outside of the Processing Areas (Lowest Risk)

  • Locker rooms, cafeterias, entry/access ways, loading bays, finished product storage areas, maintenance areas

Additional sampling sites relevant to a range of food processing facilities are shown in the table below1.

ZoneSampling Site NameTypes of Facilities Where Most Applicable
DairyMeat and PoultryProduceSeafood
1Cutting boards used for finished productXXX
1Other equipment (e.g., vats, tanks, tables) that comes in contact with product after CCPXXXX
1Brushes and other equipment that touch finished product (e.g., brushes used to brush cheeses with brine)X
1Bumper guards (e.g., on sorting tables, along conveyances) that contact finished productX
1Packaging machinesXXXX
2Racks that are used for exposed finished productXXX
2Maintenance toolsXXX
2Pipelines and exposed overhead piping in area with exposed productXXX
2Railings in finished product areasXXXX
3Floor matsXXX
3In-floor weighing equipment and floor scalesXXX
3Hoist chain bagsX
3Cleaning equipmentXXXX

Additional Resources

Environmental Monitoring Handbook
1Identification and classification of sampling sites for pathogen environmental monitoring programs for Listeria monocytogenes: Results from an expert elicitation

Are you choosing the right sampling devices?

Choosing the right sampling device is another critical factor in effective environmental monitoring.  Sampling areas will not always be flat or easy to reach, and the sampling methods employed will vary depending on the type of device being used, such as a sponge or swab, and the testing intended to be conducted.  Some key factors to consider when selecting a device are:

  • Reaches the sample target area
  • Aseptically collects the sample
  • Dislodges microorganisms from the surface
  • Neutralizes residual sanitizer

Sponges are larger sampling devices available in a variety of formats. They are the preferred choice when the area being sampled is large and readily accessible (greater than 100 cm2)​, and if qualitative pathogen testing is to be conducted. 

Swabs are smaller sampling devices that offer a tip or bud that can be particularly useful for qualitative environmental testing, for indicator organisms, for example. ​Due to their smaller size and ease-of-use for sampling a defined area, swabs are preferred for small crevices and penetrations – areas of 100 cm2 or less​. 

Additional Resources

The Environmental Sampling Approach that Supports Your Preventative Approach to Food Safety

Key Considerations for Choosing the Right Sampling Device

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