Remove It and Prove It: Better Cleaning Through Scientific Validation

Cleaning is the removal of unwanted matter, including macro soil we can see: dirt, debris, and spills; and micro soil: harmful bacteria, viruses, spores, dust particles, and chemical substances below the threshold of human perception. Micro soils, with their ability to enter the human body, often have a major impact on health, and require critical emphasis during cleaning. How do you know when you have effectively removed these micro soils that can endanger human health? In a word — measurement.

Following is an overview of three types of devices that can help validate a hygienic cleaning program that is focused on microbial and fungal micro-soil removal. Each device detects “markers” that identify a certain micro-contaminant, for example, ATP testers determine the presence of adenosine triphosphate which is present in all organic matter (bacteria, yeast, mold, food residue, etc.) to determine overall bio-soiling; bio-detectors determine the presence of antibodies, enzymes, DNA, and other components of particular living organisms, and mold detectors detect fungal enzymes as indicators of the presence of mold.

ATP Devices
ATP is the most widely recognized and accessible marker, since it enables the broadest assessment of the presence of organic soils. According to Hygiena, a leading manufacturer of ATP testing devices, “ATP (adenosine triphosphate) is present in all organic material, and is the universal unit of energy used in all living cells. ATP is produced and/or broken down in metabolic processes in all living systems. Processes such as photosynthesis in plants, muscle contraction in humans, respiration in fungi, and fermentation in yeast are all driven by ATP. Therefore, most foods and microbial cells will contain some level of naturally occurring ATP. The [ATP device] uses bioluminescence to detect residual ATP as an indicator of surface cleanliness. The presence of ATP on a surface indicates improper cleaning and the presence of contamination, including food residue, allergens, and/or bacteria… [and] potential for the surface to support bacterial growth.”

ATP results are inconsistent, however, when testing surfaces of organic nature (e.g., unfinished wood) because those surfaces have varying innate levels of ATP. “Background ATP levels can vary among building materials,” said Dr. Gene Cole, professor of Environmental Health Sciences, Brigham Young University, “thus the method must be researched according to a specific cleaning approach, the materials and surfaces to be cleaned, and the desired outcome (i.e. acceptability), in order to enhance interpretation.”

Tiled restrooms, stainless steel and tiled foodservice areas, and laminated desktops as found in schools, are ideal for ATP testing since they have no inherent ATP to skew readings.

According to foodservice inspector and National Environmental Health Association (NEHA) sanitarian, Dr. Robert W. Powitz, who holds a master’s in Public Health, with a specialty in institutional practice, and a Ph.D in environmental health from the University of Minnesota, “The more I use ATP testing in my work, and the more I explain its operational capabilities and limitations to my clients, the greater is our collective level of comfort in using it to define and set reasonable standards for cleanliness.”

ATP-based cleaning protocols are currently in development by several industry consultants and KaiScience, and will include:

1.    Flat Surface Cleaning (FSC) Protocol (Above Floor)
2.    Uneven Surface Cleaning (USC) Protocol (Above Floor)
3.    Hard Floor Cleaning (HFC) and Vertical/Horizontal and Irregular Surface (VHIS) Protocol (Above Floor)

Preliminary results data using the three initial cleaning protocols are very encouraging: FSC, USC, and HFC processes all show significant after-cleaning reductions in ATP compared to traditional methods, with labor savings. VHIS data is being gathered.

Hand-held ATP meters enable checking results on site, and within minutes of completion of cleaning, and provide a more effective way to assess cleanliness than visual inspection; an important factor in sensitive environments such as schools and hospitals. Hospital Infection magazine (published by The Hospital Infection Society) stated in 2000, “A four-part study assessing cleanliness on up to 113 environmental surfaces in an operating theatre and a hospital ward was reported. Surfaces were assessed visually, using microbiological methods and ATP bioluminescence… Using published microbiological and ATP specifications, 70 and 76 percent of… sites were unacceptable after cleaning. Visual assessment was a poor indicator of cleaning efficacy with only 18 percent considered unacceptable…”

Professor Mike Wren, biomedical scientist in clinical microbiology, University College London Hospital said: “Some of the most useful indicators of true cleanliness are ATP bioluminescence measurements….”
For the above reasons, ATP is a very promising marker for validating cleaning effectiveness.

Bio-detectors can detect specific germs, allergens, and other organisms using “biological recognition.” The device can use living bacteria, single-celled organisms, or tissues of higher organisms to detect the presence of unwanted substances based on a biological reaction. For example, if living cells inserted in the device produce antibodies in response to the introduction of a test substance, the bio-detector can identify the specific bio-contaminant based on the antibodies present. Results can be delivered within 30 to 90 minutes.

Bio-detectors developed to thwart bioterrorism may prove useful to the cleaning industry. These fall into three categories: those detecting a DNA sequence or protein that identifies the contaminant; living cells that react to specific agents and produce a measurable response; and mass spectrometry units that identify chemical components by weight and cross-match them with biological agents of known weights.

Portable DNA detection devices can now prepare and test samples within a very short time. The units basically break open bacterial spores and extract their DNA to identify the organism like a virtual "laboratory on a microchip." Procedures that used to take six hours in a lab can be done in the field in perhaps 30 minutes. Northwestern University has developed a DNA-based biochip for identifying pathogenic microorganisms. Other units are being designed for anthrax identification.
The Autonomous Pathogen Detection System, or APDS, monitors the air like a smoke detector, and can detect and identify bacteria, viruses, and toxic substances.

Mold Detectors
Mold detectors are hand-held portable devices that detect fungal enzymes to determine total fungal biomass. Though the units cannot differentiate between types of mold, they can accurately determine on site within one hour the presence of fungi, and the effectiveness of mold remediation on surfaces including wood, grout, and various building materials.
“Our experience with [a mold detector] as the final clearance methodology for HVAC and mold remediation has been excellent… [it] documents the… efforts of our technicians,” said Tim Herbert, of Air Purification Specialists, Inc.

According to Gene Cole: “Comparative research is necessary to identify optimum cleaning effectiveness measurement methods for specific target markers across different environments, materials and surfaces, and applications. Such research, conducted in a cooperative mode of effort, will serve to define the many aspects of ‘clean,’ and help to establish consensus standards of care for ‘cleaning effectiveness’ within the industry.”

In short, science now provides us with technology-assisted “eyesight” to detect generally invisible micro-soil, then remove it, and prove it. This helps us realize cleaning’s ultimate purpose and potential — to protect people from unseen environmental harm.

Allen P. Rathey is the director of KaiScience, an online community whose mission is to foster cleaner, healthier indoor environments through science.