Traditionally, food safety and quality systems were mostly supported by the analysis of final product​. This reactive approach required waiting for a final product’s status to trigger action against contamination.  

As food safety regulations have evolved and customer expectations for safety have intensified, we’ve seen a shift toward proactive and preventive strategic approaches for environmental monitoring, which can minimize food contamination and enhance overall food safety and quality. As you build or enhance your program, it’s important to consider how you will approach sampling your processing environment. 

How do you focus on preventing food safety issues?  

Rocio Foncea, 3M Food Safety global technical service scientist, says that a proactive approach establishes interventions to minimize risk of contamination. This means shifting testing priorities from finished product testing to a strategic approach that identifies and eliminates sources of contamination. A well-designed environmental monitoring program will include samples from various areas throughout your production process. When designing your program, you should focus on three primary goals:  

• Finding pathogens in the environment before they contaminate product​ 
• Finding spoilage microorganisms in the environment before they affect product​ 
• Assessing effectiveness of cleaning, sanitation, and hygiene practices  

To achieve these goals, let’s explore four key aspects of environmental sampling.  

Investigate Growth Niches 

An environmental monitoring program can play a key role in not only improving the safety of food products, but also helping with identifying and eliminating or managing growth niches. Growth niches are locations that support microbiological growth and are protected from the sanitation process. They’re hard-to-reach areas like cracks or crevices. ​Growth niches are characterized by high microbial counts after cleaning and sanitation​ and are a potential place for the formation of biofilms. They may also trap nutrients and water, which can promote the growth of bacteria. ​ 

A key step in your approach to environmental monitoring involves investigating where growth niches may be hiding in your food processing environment, and sampling based on these zones:  

• Zone 1: food contact surfaces (surfaces directly contacted by an exposed ready-to-eat or RTE food, finished product)​ 
• Zone 2: non-food contact surfaces close to Zone 1 (equipment frames, control panels and buttons, computer screens, etc.)​ 
• Zone 3: non-food contact surfaces located in in or near processing areas (floors, walls, drains, ceilings, etc.)​ 
• Zone 4: representing areas outside from the RTE area (locker rooms, loading docks, entry/ access ways, etc.) 

Multiple sampling sites from each zone should be determined, based on the specific facility design and processes, before you begin taking samples.  

Determine the frequency of sampling​ 

Once you’ve identified the zones where growth niches may be hiding, it’s time to decide how often you’ll sample and how many samples you’ll take. The standard guidance for sampling frequency and number of samples suggests that both should be determined based on risk.  

Generally, facilities where ready-to-eat (RTE) food is exposed to the environment would be considered high-risk, requiring, at a minimum, weekly sampling for target pathogens.​ Facilities in which environmental monitoring results frequently reveal poor sanitation or emerging microbial harborage sites should increase the frequency of sampling. ​ 

Both frequency and the number of sites increase as size of the facility, pace of production, age of the facility and equipment, and quality threat risk aversion increase.  

Selection of the sample collection device and sampling methods​ 

After assessing your facility and determining your frequency of sampling, next you’ll want to choose your collection device and sampling methods. 3M Food Safety expert Rocio Foncea says you should select a sample collection device that:  

• 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 (e.g., for indicator organisms). ​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)​.  

Keep in mind that sampling methods employed will vary depending on the type of device being used and the testing intended to be conducted. Many growth niches needed to be sampled are not flat areas or may not be easily accessible. A good sampling method takes these challenges into account. 

Selection of the sampling neutralizers​ 

Another important aspect of environmental sampling is the selection of sampling neutralizers. Sampling from food processing environments can present several challenges, including the presence of sanitizers that may continue to have bactericidal or bacteriostatic activity after the sampling event. 

Sample collection devices should incorporate components that are effectively able to neutralize any sanitizers present.​ Several factors, such as the type and concentration of sanitizer, can impact your ability to neutralize it.  

When selecting a neutralizer (or combination of neutralizers), you first need to know the types of sanitizers used within a facility, and if a particular sampling neutralizer can handle the type and level of sanitizer that may be in the surface. Common neutralizers include Letheen Broth, D/E Neutralizing Broth, Neutralizing Buffer and Buffered Peptone Water. Use the below chart as a guide in your selection.  

Environmental Monitoring Handbook for the Food and Beverage Industries. 1st. Ed. 3M and Cornell University. 2019.​ 

Looking for more resources?  

A proactive environmental monitoring program is an important part of minimizing food contamination and enhance overall food safety and quality. The above are key considerations as you develop your approach, and if you’re interested in learning more, here are some helpful resources:  

• Explore the 3M™ Petrifilm™ Plates Environmental Monitoring Procedures. 
• Download the Environmental Monitoring Handbook for the Food and Beverage Industries. 
• Register for the Environmental Sample Collection Strategies and Methods webinar on August 18. 

Other questions? 

Want more information on how 3M Food Safety can support your environmental monitoring program? Simply reach out and we’ll be happy to help.