Tag Archives: cleaning

Sponges, environmental sampling

Mitigate the Risk: Importance of Environmental Sampling in an Environmental Monitoring Program

By Gabriela Martinez, Ph.D.
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Sponges, environmental sampling

There are several ways in which pathogens can enter a food processing facility. Once inside, pathogens are either temporary visitors that are removed using cleaning and disinfection methods, or they can persist in sites such the floor or drains and require a more intense remediation process. As food processors take on the responsibility to prevent product adulteration in facilities, setting up and maintaining an environmental monitoring program (EMP) is critical.  An effective EMP helps a company manage and potentially reduce operational, regulatory and branding reputation risks.

Establishing an EMP begins with identifying and documenting potential pathogen sources in all physical areas (including raw materials, storage and shipping areas) and cross-contamination vectors (employees, equipment, pests, etc.). These areas and vectors should be surveyed, controlled and when possible, eliminated. Implementing effective controls, including microbiological sampling of high-risk areas, should be part of the program. Sampling for pathogens or indicator microorganisms  in food contact areas during production is also important. Additionally, the EMP elevates the awareness of what is happening in the plant environment and helps companies measure the efficiency of their pathogen-prevention program—for example, it is not only critical to test for pathogens, but also for the overall effectiveness of cleaning and sanitizing procedures. Both procedures are necessary and must be properly executed to reduce microorganisms to safe levels. The goal of a cleaning process is to remove completely food and other types of soil from a surface. Since soils vary widely in composition, no single detergent is capable of removing all types. In general, acid cleaners dissolve alkaline soils (minerals) and alkaline cleaners dissolve acid soils and food wastes. It is for this reason that the employees involved must understand the nature of the soil to be removed before selecting a detergent or a cleaning regime. The cleaner must also match with the water properties and be compatible (i.e., not corrosive) with the surface characteristics on which it will be applied. However, not only the correct choice of agent is necessary for an optimal result; it should be coupled with a mechanical action, an appropriated contact time and correct operating temperature. As the combination of these parameters is characteristic to each process, it becomes essential to verify effectiveness through sampling. Finally, cleaning is closely related to sanitation, because it can’t be sanitized what hasn’t been previously cleaned.

“Not Your Grandfather’s Environmental Monitoring Program Anymore”: Learn more about this important topic at the 2016 Food Safety Consortium | EVENT WEBSITE

The Association of Official Analytical Chemists defines sanitizing for food product contact surfaces as a process that reduces the contamination level by 99.999% (5 logs). Sanitation may be achieved using either heat (thermal treatment) or chemicals. Hot water sanitizing is commonly used where immersing the contact surfaces is practical (e.g., small parts, utensils). Hot water sanitizing is effective only when appropriate temperatures can be maintained for the appropriate period of time. For example, depending on the application, sanitation may be achieved by immersing parts or utensils in water at 770 C to 850 C for 45 seconds to five minutes. The advantages of this method include easy application, availability, effective for a broad range of microorganisms, non-corrosive, and it penetrates cracks and crevices. However, the process is relatively slow, can contribute to high energy costs, may contribute to the formation of biofilms and may shorten the life of certain equipment parts (e.g., seals and gaskets). Furthermore, fungal spores can survive this treatment.

Regarding chemicals, there is no perfect chemical sanitizer. Performance depends on sanitizer concentration (too low or too high is ineffective), contact exposure time, temperature of the sanitizing solution (generally, 210 C to 380 C is considered optimal), pH of the water solution (each sanitizer has an optimal pH), water hardness, and surface cleanliness. Some chemical sanitizers, such as chlorine, react with food and soil, becoming less effective on surfaces that have not been properly cleaned.

The effectiveness of a plant’s sanitation practices must be verified to ensure that the production equipment and environment are sanitary. Operators employ several methods of verification, including physical and visual inspection, as part of ongoing environmental hygiene monitoring programs. Portable ATP bioluminescence systems are widely used to obtain immediate results about the sanitary or unsanitary condition of food plant surfaces. ATP results should be followed up with more in-depth confirmation testing, such as indirect indicator tests and pathogen-specific tests. Indirect indicator tests are based on non-pathogenic microorganisms (i.e., coliform, fecal coliforms or total counts) that may be naturally present in food or in the same environment as a pathogen. These indicator organisms are used to assess the overall sanitation or environmental condition that may indicate the presence of pathogens. The principal advantages of using indicator organisms in an EMP include:

  • Detection techniques are less expensive compared to those used for pathogens
  • Indicator microorganisms are present in high numbers and a baseline can be easily established
  • Indicator microorganisms are a valid representative of pathogens of concern since they survive under similar physical, chemical and nutrient conditions as the pathogen

However, indicator organisms are not a substitute for pathogen testing. A positive result indicates possible contamination and a risk of foodborne disease. It is recommended that samples be taken immediately before production starts, just after cleaning and sanitation have been completed when information regarding cleaning and sanitation are required. However, when sampling is conducted on surfaces previously exposed to chemical germicide treatment, appropriate neutralizers must be incorporated into the medium to preserve viability of the microbial cells.

Neutralizers recommended for food plant monitoring include Dey-Engley neutralizing broth (DE), neutralizing buffer (NE), Buffered peptone water (BPW) and Letheen broth (LT) (see Table I). Most of these are incorporated into a support such as a sponge, swab or chiffon to neutralize the residues of cleaning agents and sanitizers that may be picked up during swabbing. The product should be selected based on the surface, the type of cleaning agents and the type of testing (qualitative or quantitative).

Neutralizing agents, Environmental sampling
Table I. Neutralizing agents

It is critical to verify that the chosen neutralizer has an efficient action against the used sanitizers. Table I show the most effective equivalence among the cleaning agents and the most common neutralizers.

For instance, if a quantitative method is to be used, it is very important to consider a neutralizing agent, such as the neutralizing buffer, that doesn’t support the bacterial growth.

Finally the sponge is a very popular choice due to its versatility. Sponges are used for sampling equipment surfaces, floors, walls, work benches and even carcasses. They enable the sampling of large surfaces and the detection of lower levels of contamination at a lower cost of operation.

Sani sponge
The versatility of sponges make them a popular choice for environmental sampling. Image courtesy of Labplas.

To summarize, environmental sampling is an important tool to verify sources of contamination and adequacy of sanitation process, helping to refine the frequency and intensity of cleaning and sanitation, identify hot spots, validate food safety programs, and provide an early warning of issues that may require corrective action. Over all, it provides the assurance that products being manufactured are made under sanitary conditions.

Color coding to enable allergen and potential contamination distinction

If You Aren’t Color Coding Yet, You’re Way Behind

By Bob Serfas
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Color coding to enable allergen and potential contamination distinction

Since the introduction of FSMA, food safety has been under a much-needed magnifying glass. Standards for hygiene and accountability are increasing, and companies are implementing more measures to keep consumers safe. One of the ways in which businesses are being proactive is through implementing color-coding plans. If you have not heard of this type of plan yet, it’s time to get schooled; and if you have, this article will provide a quick refresher on why companies are expanding their spectrum on contamination prevention—by literally implementing the color spectrum in their plants and businesses. 

What Is A Color-Coded Plan?

A strategy for a plant or business that designates certain colors for a specific area or purpose designed to promote safety and cleanliness.

Example Plans. Although color-coding plans vary by the needs and demands of each plant, the following are the most popular types of color-coding plans currently being practiced in food manufacturing.

Color coding to enable allergen and potential contamination distinction
Color coding a cleaning brush can help employees make the distinction when dealing with allergens and potential contamination. All images courtesy of Remco/Vikan

Allergen/Potential Contaminant Distinction

Food Processors and manufactures usually have identified potential allergens and contaminants that pose a risk to the production process. Color distinction for equipment or instruments that come into contact with these potential contaminants is an ideal tool for food safety. Determining the amount of items that fall into this category within your facility is the first step to selecting the appropriate amount of colors to implement. The most basic color-coding plan for this purpose would be to select one color to represent tools that come into contact with a particular risk agent and one color to represent those tools that may be used elsewhere. If a plant has more than one risk agent, this plan may be expanded to include several colors. It is important to remember, however, that simplicity is key in color coding and that additional colors should be implemented strictly on an as-needed basis.

Zone Distinction

Many plants already have identified zones in place based on what is produced in each zone or simply due to operating a large plant. This presents an ideal opportunity to color code zones to keep tools in their proper place.  

Shift Distinction

Certain plants that have a large number of employees working different shift times should also consider color coding. Color coding by shift can hold each shift responsible for proper tool use and storage. This approach also allows management to see where work habits may be falling short and where the cost of tool replacement is highest. 

Assembly Process Distinction

Plants that have assembly line-like processes can implement color coding if necessary to differentiate tools that belong to each step. For example, this becomes particularly important in plants that deal with products such as meat; obviously you do not want to use the same tools with raw and processed meat. Color coding eliminates the question of whether or not a tool is meant for each step in the process.

Color coding for cleaning purpose distinction
Implement a two-color-coding plan to distinguish between tools used for cleaning versus sanitation.

Cleaning Purpose Distinction

For many food plants, cleaning and sanitizing are processes that are considered different in purpose and practice. Often, there is a specific list for cleaning and then a separate plan for sanitizing. Implementing a two color-coding plan can distinguish tools that are meant for each process.

Why You Need A Color-Coded Plan

It helps meet FSMA requirements. A major part of complying with FSMA regulations is having proper documentation to prove safety measures. Color-coding plans do exactly that, and most providers of these products can provide you with the necessary documentation.

It reduces pathogens and allergens contamination. For food producers, this is the most important reason to implement color coding. There is nothing worse for a company than experiencing product contamination or a recall; this is one step that may prevent such events from occurring. 

It is easy to understand. Color coding works so well because it is so simple. All employees, even those who may not speak the same language or are unable to read posters and manuals that dictate proper procedures, can easily comprehend it.

It creates a culture that holds employees accountable. Managers enjoy color-coding practice because it is a simple measure that really works to hold employees accountable in the proper use of tools. It becomes much more obvious when a brightly colored tool is out of place, and thus workers are more likely to follow proper procedure.

Using ATP-based Methods for Cleaning and Sanitation Verification

By Camila Gadotti, M.S., Michael Hughes
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There are several factors that must be considered when selecting a reliable and accurate system for detecting adenosine triphosphate.

A common way to assess the effectiveness of cleaning and sanitation programs in food manufacturing facilities is through the use of methods that detect adenosine triphosphate (ATP). Methods based on ATP detection are inexpensive and rapid, and provide the ability to perform onsite in real-time. There are several manufacturers of ATP-based methods, but choosing the most reliable one can be a daunting task. This article will discuss how these methods work and which factors should be considered to make an informed purchasing decision.

ATP is the universal energy currency in all living cells. It is present in all viable microorganisms (with the exception of viruses) and in foodstuffs. High amounts of ATP can be found in some fresh foods like vegetables, while other foods, especially highly processed foods such as fats, oils or sugar, contain very low amounts of this molecule. It is also important to know that ATP can be found in the environment in its free form hours after a cell has died.1 An ATP bioluminescence assay operates on the principle that ATP in food/food residues and microorganisms, in the presence of a luciferin/luciferase complex, leads to light emission. This light can be measured quantitatively by a luminometer (light-detecting instrument), with results available in 10–40 seconds. The amount of light emitted is proportional to the amount of ATP on a surface and hence its cleanliness. The light emitted is typically measured in relative light units (RLUs), calibrated for each make of instrument and set of reagents. Therefore, the readings obtained from assessing the cleaning of food manufacturing facilities need to be compared with baseline data representing acceptable clean values.

Varying Optical Components

Luminometers have evolved over the years from very large and cumbersome in size to small handheld models that can be used anywhere within a manufacturing facility. Although several components are housed inside these instruments, the optical component is the most important part of a luminometer. Used to detect light coming from the ATP/luciferin/luciferase reaction, the optical component is the defining factor related to luminometer reliability, sensitivity and repeatability. Good luminometers use a photomultiplier tube (PMT) in the light detection system; however, as part of the drive toward cheaper and smaller instruments, some manufacturers have replaced PMTs with less-sensitive photodiode-based systems. When using photodiodes, the swab chemistry must be adapted to produce more intense light. This results in a shorter duration of light, decreasing the time window allotted to place the swab in the luminometer and obtain an accurate read. A PMT, however, multiplies the electrical current produced when light strikes it by millions of times, allowing this optical device to detect a single photon. This approach emits light over a longer period of time. Although the weight of the system is also dependent on factors such as the battery, case and the display screen, a luminometer constructed with a photodiode will generally weigh less than a luminometer constructed with a PMT, since the former is smaller than the latter.

Sensitivity Testing

When an ATP hygiene monitoring system has poor sensitivity or repeatability, there is substantial risk that the test result does not truly represent the hygienic status of the location tested. Therefore, it may provide false positives leading to unnecessary chemical and labor costs and production delays, or false negatives leading to the use of contaminated pieces of equipment. A system that is sensitive to low-level contamination of a surface by microorganisms and/or food residues allows sanitarians to more accurately understand the status of a test point. The ability of a system to repeat results gives one peace of mind that the result is reliable and the actions taken are appropriate. To test different ATP systems for sensitivity, one can run the following simple test using at least eight swabs per system:

•    Make at least four serial dilutions of a microbial culture and a food product in a sterile phosphate buffer solution.
•    Using an accurate pipette, dispense 20 μl of these dilutions carefully onto the tip of the swabs of each ATP system and read the swabs in the respective luminometer, following the manufacturer’s instructions.
•    Use caution when dispensing the inoculum onto the swab head to prevent any sample loss or spillage. In addition, it is very important the swabs are inoculated immediately prior to reading, which means that each swab should be inoculated one at a time and read in the respective luminometer. Repeat this process for all the swabs.


To test different ATP systems for sensitivity, one can run a simple test using at least eight swabs per system. Photo courtesy of 3M

The most sensitive system will be the one that results in the most “fail results” (using the manufacturers’ recommended pass/caution/fail limits).

One can also test different ATP systems for repeatability by the following test:

•    Prepare a dilution of a standard ATP positive control or a food product such as fluid milk in a sterile phosphate buffer. If using a standard ATP positive control, follow the manufacturer’s direction to prepare dilution. If using fluid milk, add 1 ml of milk into 99 ml of phosphate buffer.
•    Using an accurate pipette, dispense 20 μl of this standard onto the tip of the swabs of each ATP system and read these swabs in their respective luminometer, following the manufacturer’s instructions.
•    Prepare and read at least 10 swabs for each system you are evaluating, and capture the results on a digital spreadsheet.
•    Once all 10 swab results (for each system) are in the spreadsheet, calculate the mean (=average) and standard deviation (=stdev) for each system’s data set. Divide the standard deviation by the mean and transform the result in percentage; this value is called the coefficient of variation percentage (CV%).
The test with the lowest CV% is the most repeatable and will provide the most reliable information to help make the correct decisions for a food manufacturing facility.

Choosing the Right ATP System

There are many ATP systems available on the market to support cleaning and sanitation verification in manufacturing plants. Some systems are more reliable than others and will provide results that are meaningful, accurate and repeatable. Be sure, therefore, not to choose a system solely based on its price. Check for the quality of the instrument, ask the sales representative what kind of optical device is used in the construction of the instrument and, moreover, perform an evaluation running tests for both sensitivity and repeatability. It is also important to consider the functionality and usability of the software provided with the system to ensure that the software can be used to customize sample plans, store test results and produce reports and graphs.


  1. Jay, J. M., ‎Loessner, M. J., & Golden, D. A. (2008). Modern Food Microbiology.


About the Author:

Camila Gadotti, M.S., is a field technical service professional and Michael Hughes is a technical service professional with 3M Food Safety.

Sangita Viswanathan, Former Editor-in-Chief, FoodSafetyTech

How Effective is Your Cleaning and Sanitation Program?

By Sangita Viswanathan
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Sangita Viswanathan, Former Editor-in-Chief, FoodSafetyTech

Cleaning and sanitation programs are indispensable in a food manufacturing plant, as they assure the safety and quality of food being produced. These programs are also key in protecting the integrity of your brand. Because of these programs’ importance, 3M Food Safety sent out a survey this summer toFood Safety Tech readers to learn more about how their manufacturing plants are checked for cleaning and sanitation effectiveness.

Here is what we heard back from 155 respondents:

  • Only 5.8 percent do not perform any type of cleaning and sanitation validation program in their facilities.
  • Of the 94.2 percent that do have a cleaning and sanitation validation program in place, 92 percent use more than one method to verify cleaning and sanitation effectiveness.
  • The methods of choice in order of higher preference were: visual check (86.8 percent), microbial testing (80.5 percent), ATP swabs (70.1 percent) and protein swabs (25.7 percent).
  • The most used combination of tests was visual checks along with ATP swabs (70 percent).

Analyzing the survey results, Camila Gadotti, Professional Service Account Representative for 3M Food Safety Department was surprised there were still a proportion of respondents (though small) who didn’t have a cleaning and sanitation program in place. “This is such an important part of food safety and quality, and yet we still have some people who don’t have a program in place. Also majority of people still rely on visual check, which is not a good system for a sanitation program.”

Since respondents could check more than one choice for which method they used, a lot of people did visual check in conjunction with other microbial or ATP swab testing. Of these methods, Gadotti pointed out that microbial testing, given that it could take 24 to 48 hours to get results, would be a slow process. “In this time frame, the product could have been sold in the market. So while the test results could still be used for corrective steps to improve sanitation, it’s not the ideal choice for testing.”

Instead, ATP swabs would be a faster and more sensitive alternative, she adds. “ATP swabs work on the science that every live cell contains ATP. This is not just microbial cells, but also product residue, which will generate light based on the chemistry of the product. And results are back in 10 seconds. So you can walk around, collect swabs, put them in the illuminator, and you will very quickly get a number, which is the Relative Light Unit. If the RLU level is considered safe, the facility is clean.” With new and stricter regulations on the food industry horizon, companies are increasingly moving to adopt ATP swab for their sanitation programs, says Gadotti.

Besides which method to choose, another important step in creating a cleaning and sanitation validation plan is the number of sampling sites to be tested. Readers were asked how many locations they test for and there was a wide spread of answers:

  • 65.3 percent test between 5 to 20 different locations in their plants for cleaning and sanitation effectiveness;
  • 14.6 percent of the respondents test between 20 to 30 locations;
  • 6.2 percent of the respondents test between 30 to 40 locations;
  • 3.5 percent of the respondents test between 40 to 50 locations; and
  • 10.4 percent of the respondents test more than 50 locations.

The respondents of this survey work in facilities that range from fresh cut fruits and vegetables to dairy, confectionery, meat and poultry plants. Each of these facilities chose validation methods that were deemed appropriate to support their cleaning and sanitation plans in their manufacturing plants. Although some methods are more common than others, choosing the right method for each processing plant will depend on factors like the type of food being produced, turn-around time, product label claims and, of course, cost.

Another observation from the survey was that people still see verification of sanitation program as an expense. Instead companies need to view this as an investment for the company and its food safety program, Gadotti says.

“Verifying the effectiveness of your cleaning and sanitation program does not need to be a lengthy and troublesome task. Adopting a couple different methods of verification, such as visual checks, microbial testing and/or ATP swabs, tested for in a couple dozen strategic locations throughout your plant should suffice to verify that your plant has been properly cleaned and sanitized. Remember, verifying cleaning and sanitation may help you prevent many issues like reduced shelf-life in your products and unnecessary product recalls,” she sums up.