Posts Tagged ‘Sanitization’

THE SANITARIAN’S FILE Activated and Electrolyzed Water: A Brief Review of a New Generation of Cleaners and Sanitizing Agents

August 12, 2010

By Robert W. Powitz, Ph.D., MPH

August/September 2010

// A new technology has taken the housekeeping industry literally by storm this past year. It is activated water. The recent threat of an H1N1 pandemic severely impacting our public health prompted new and innovative ways for spot cleaning, particularly to clean frequently touched surfaces (frequently referred to as “high-touch” or “common-touch”) in institutions in which the flu finds an ideal fomital transmission environment, such as schools, hospitality, recreational and correctional facilities.

Because several states, as well as the U.S. Federal Government, are aggressively urging the housekeeping industry to embrace the concept of sustainability and green cleaning, coupled with the U.S. Environmental Protection Agency (EPA)’s Tools for Schools initiative, the housekeeping professionals have responded by seeking better ways of cleaning with products of lower toxicity and zero persistence in the environment. Not surprisingly, nothing meets this criterion better than water.

As sanitarians in the public health arena, we are not only concerned with cleaning but also with significantly reducing the bioburden as we clean. Additionally, by way of disease prevention, maintaining the potential bioloads of these surfaces as low as possible, under practical and cost-effective conditions, makes the use of water, in any form, ideal.

Disinfectant versus Sanitizer
However, before I go on to explain the phenomenon of activated water products and their potential use in the retail food industry, let me first take this opportunity to clarify the terminology we use in its description and to place activated water in the proper context of cleaning and bioload reduction.

Activated water closely fits the criteria of cleaner and “sanitizer” versus that of a “disinfectant.” To make this distinction, I found an excellent short lexicographic essay written by someone at Hillyard Chemical. I am taking the liberty of paraphrasing this piece for brevity of explanation.

The difference between a “disinfectant” and a “sanitizer” is one of application. Whereas the health care industry is mainly interested in “disinfectant” data, the foodservice-related industries guided by the Public Health Services are primarily concerned with “sanitizer” claims. The actual difference between the two terms is, to some extent, a matter of legal definition. In current American regulatory parlance, a disinfectant is a product that completely destroys all specific test organisms in 10 minutes under conditions of the AOAC Use Dilution Test, whereas a sanitizer is a product which destroys 99.999% (or a 5-log reduction) of specified test bacteria in 30 seconds under conditions of the Official Detergent Sanitizer Test. Obviously, both deal with different aspects of the same problem: killing bacteria.

Interest in the use of germicides used in hospitals centered on completely destroying all possible microorganisms. In the normal course of hospital application, it was felt practical to allow at least 10 minutes of contact time to accomplish this objective. As a result, most disinfectant tests were developed to ascertain whether any bacteria survived 10 minutes of germicide contact—nothing more, nothing less. In fact, when contact times significantly less than 10 minutes are allowed, it becomes very difficult to get any kind of meaningful results out of the Use Dilution Test.

In foodservice and other public health-related industries, interest in germicides took a different approach. It became obvious that the conditions of use differed from hospitals and that tests based on 10 minutes of contact time could not be satisfactorily interpreted. Public health professionals reasoned that 30 seconds was about all the contact time they could realistically expect. Nevertheless, the prevailing disinfectant tests could not yield 30-second results. Therefore, they developed their own test—the Official Detergent Sanitizer Test.

Because the public health scientists did not anticipate that they could actually get complete kill in 30 seconds with any practical chemical agent, they developed a test in which bacteria are actually counted. They found that a 99.999% reduction in 30 seconds with practical agents was quite acceptable for the intended application and adopted this standard. To distinguish these products from disinfectants, they called them sanitizers.

The 5-log reduction rule of sanitizing took on new meaning when applied to newer methods for getting surfaces biologically clean. Validation of surface cleanliness with particle counting and adenosine triphosphate (ATP) let us redefine “clean” in a completely different context: where the 5-log reduction in organisms could actually be obtained through the physical act of cleaning. This meant that on a smooth surface, we could accurately measure the initial bioburden in negative log numbers by increasing the area of the test in much the same dynamic as determining the more traditional D, Z and F values we use for temperature and mass differences. After cleaning, we can now easily determine 5-log reduction estimates by measuring total ATP levels. Since microbial removal is part of overall biological cleanliness, it can be assumed that we can achieve a state of ‘sanitization’ using the same criteria that we do for hot water rinses in warewashers. Thus, from the applied data found in refereed journals and contract laboratory analyses, activated water has found a niche in chemical-free cleaning, with results quite comparable to those of sanitizing agents. In short, when used judiciously and with validation, activated water can replace chemical sanitizers in many applications in the retail food industry.

How Activated Water Products Work
There is considerable confusion about how the current generations of activated water cleaning products work. First, they all start with plain, potable, tap water. The water must be conductive. While most conventional products clean and sanitize based on chemical reactions, the newer, solid-state-activated water sprayers and scrubbers work mainly on principles of physics and electrical engineering. Contrary to popular perception, the process is not solely or mainly based on typical electrolysis. The technology does however use electrolysis, causing almost imperceptible pH and other changes in water chemistry, but these barely measurable effects are not the “active ingredients” used to clean.

Applying a small amount of electricity to water breaks down the water’s molecules, lowering its natural surface tension and creating positively and negatively charged water ions. When applied to a surface in this electrolyzed form, water can spread to contact dirt, just as it does when mixed with chemicals. The charged ions in the water attach to the dirt and help lift it from the surface.

In addition, water electrolysis is actually applied to “create” charged, nano-sized gas bubbles in the water. These electrically charged bubbles attach themselves to dirt particles, causing the particles in turn to become charged and repel from surfaces, thus enabling soils to be suspended in water and wiped away. Soil removal performance tests were developed and conducted by the University of Massachusetts’ TURI Lab. Most testing was performed to a modified ASTM G122 Test Method, a modified version of the Green Seal GS37 standard, the CSPA DCC 17 – Greasy Soil Test Method or the CRI Carpet Spot Cleaning TM 110 standard. The results clearly show that activated water cleaning works effectively on most common soils, including those found in food production.

As a sanitizing agent, the main “ingredient” behind the germ-killing effect of modern activated water devices is electroporation. This is a scientific process that applies a low-level electrical field to bacteria or viruses. This electrical charge creates holes or “pores” in the membrane of the cell, which breaks down the walls of the bacterial cells and kills them. It is also believed that pathogenic viruses are affected in the same way. Only when the unit is activated in which the water acts as a conductor does electroporation occur. With the newer hand-held devices, this entails spraying the surface constantly for 6 seconds to sanitize it. EPA-compliant Good Laboratory Protocol tests show that it works and is an effective, broad-spectrum sanitizer. One of the benefits of the electroporation technology is that it does not require contact or dwell time for efficacy. Contact with the spray itself was shown to cause an immediate 3-log reduction without any additional help from flushing or mechanical soil removal. Furthermore, the electrically activated water is completely safe and returns to its natural state in about 30 to 45 seconds. Studies show that electrically activated water cleans as well as, or better than, traditional general-purpose cleaning chemicals.

Electrolyzed Water
There is yet another cleaning method that predates activated water but uses tap water and table salt. It is commonly dubbed electrolyzed water where ions are basically scrambled by an electric current. Unlike activated water, it relies on contact time for its efficacy as a cleaner and sanitizing agent. The generators use a combination of cell technology, salt and electricity to alter the molecular structure of water, creating a non-toxic, oxidized, antimicrobial solution that is capable of killing many pathogens in less than a minute. Opposed to smaller, hand-held devices with activated water, this is an in situ technology that has been used as an effective cleaner and broad-spectrum sanitizer for decades in Russia and Japan, and is finally winning acceptance here in the U.S. and Canada.

The sanitizing characteristics are a bit different in this technology. The high oxidation of the water first damages bacterial cell walls, allowing infiltration by water. The microbe reaches capacity, causing an osmotic, or hydration, overload. The acidic fluid and water floods the cell more rapidly than the cell can expel it, literally causing the cell to burst.

Although the initial cost for the water electrolysis unit is somewhat high, it can often be amortized in 1 year by replacing conventional cleaners in mop buckets, sprayers and anywhere harsher and more toxic cleaning chemicals are currently used or needed. In addition, it has no odor, nor does it produce foam, making it ideal for use in food production. There are numerous citations in the scientific and industry literature that this technology has effectively demonstrated excellent cleaning ability in the dairy, poultry and produce industries. Test results showed that for a dwell time between 7.5 to 10 minutes, electrolyzed water was as effective in removing organic matter as conventional treatments, making this technology ideal for general use in retail food establishments.

These technologies show great promise, limited only by our imagination. I predict that full approval and acceptance of both activated and electrolyzed water as cleaners and sanitizers in the retail food industry will soon become a reality.

On a personal note, activated water hand-held generators have been used in my home for general cleaning for over a year. I have used both ATP swabs and RODAC plates in various small experiments in which comparisons were made between activated water and brand-name household chemicals purchased from my local supermarket. I found virtually no difference between the two. Because the activated water generator is always available and requires a mere press of the trigger, it is used considerably more often than the conventional cleaners. Being a bit lazy, the idea that there is no additional bucket, dilution or mixing involved makes this technology particularly appealing. While it does not entirely replace all cleaning products, it has had a profound effect in reducing chemical use in my home (a good thing because I have a septic system) and has markedly improved overall cleanliness, particularly in the bathrooms.

If it works well for me, it certainly can work well in our industry. Going green has never been easier, and the more we know about these technologies, the greater the potential for overall food safety. As regulators, we need to embrace these technologies as soon as possible—regulations permitting. ♦

Forensic sanitarian Robert W. Powitz, Ph.D., MPH, RS, CFSP, is principal consultant and technical director of Old Saybrook, CT-based R.W. Powitz & Associates. Feedback or suggestions for topics you would like to see covered can be sent to him directly at or through his Web site at

©2010 The Target Group, Inc.   All rights reserved.


March 25, 2010

Accurate dosing is a prerequisite for efficient and cost-effective sanitation. The equipment and procedures which are used to deliver sanitizer solutions vary and depend on the specific application for which they were intended and the industry being serviced.


In large food processing plants, daily clean-up necessitates sanitation of all food contact surfaces. Measured quantities of sanitizer are generally transferred from the drum into a large (500 to 1000 liters) dedicated tote, using a calibrated metering pump. The required volume of water is then added to a predetermined level to make up the end-use solution. The amount of sanitizer which the pump is capable of delivering is based on the volume displaced by each stroke of the pump and the time period that the pump is in actual operation. The volume of each stroke can be adjusted and fine tuned rendering the system capable of dosing accurate and consistent concentrations of sanitizer. More sophisticated equipment (and more expensive) use wall mounted pumps which are electronically connected to water flow meters. As water flows into the dispensing tote, it triggers the pump to operate on an intermittent basis to deliver calibrated quantities of sanitizer, with each transfer to the tote of a predetermined volume of water. This intermittent cycle of dosing provides for a more uniform mixing of sanitizer with water. To insure complete dispersion of sanitizer in solution, large storage tanks also have auxiliary pumps and the capability of recirculating the solution for several minutes.

Since effective sanitization in food processing plants is a crucial step in the over all clean up procedure, the crew leader will usually sample the diluted sanitizer solution using either a test kit or test paper. Once adjustments and verifications, if required are made, the sanitizer solution is applied under low pressure onto the food contact surfaces and the excess is allowed to freely run off. Low pressure applications are preferable since they reduce the risk of generating airborne mists which can cause dislodge bacteria to become airborne and transported over great distances. Following sanitization, a potable water rinse is not required nor is it recommended. Flat horizontal or vertical surfaces can either be air dried or allowed to remain wet. The later method is the preferable one and used more frequently. Leaving the surface wet prevents airborne bacteria which may settle on food processing equipment and tables from surviving therefore decreases the risk of contamination.At start-up of operations during the following shift, the remaining residual sanitizer can be rinsed off prior to handling food products. This is not a mandatory or regulatory requirement since sanitizers used in food processing plants also have clearance for incidental food contact at the concentrations used.

The areas within a Supermarket deli, meat and bakery sections are relatively small and the equipment requirements for clean up and sanitation can be carried out with simple equipment. Blades, knives, saws, scrapers, and other small utensils are disassembled from the food cutting or processing equipment and placed into a three compartment sink. First, they are allowed to soak in a detergent solution which is dispensed into the sink through a wall mounted plunger type of hand pump. The components are then rinsed with water in the middle sink and sanitized by immersion into the third, sanitizer-containing compartment. Sanitizer is dispensed into the third sink compartment in a manner similar to that used to dispense detergent.
The stationary portion of the equipment as well as the cutting tables are first cleaned with a high foaming detergent then sanitized with a low level disinfectant such as a quat. The equipment used in this type of operation is usually a commercial version of a garden hose sprayer and using city water pressure as a means of delivering product to the affected surfaces. Water flowing through the hose also creates a partial vacuum within the garden sprayer resulting in sanitizer solution being drawn up and mixing with the water stream as it flows past the garden sprayer’s orifice. Commercial units designed for sanitizer application are accurately calibrated by the manufacturer to dispense a 0.2% solution, which is equivalent to 200 ppm quat (10% active) or 200 ppm available chlorine (10% sodium hypochlorite).
Small, pressurized portable tanks into which a prediluted sanitizer solution has been added also finds use in this application, especially in enclosed areas where sanitizer has to be applied to surfaces that are not readily accessible. Such a system makes use of the pressurized contents to direct a stream of sanitizer over a larger distance than would be possible with a garden sprayer using city water pressure.

Large hospitals and nursing homes usually dispense use-solution from stationary, central units; each one located on a separate floor. Frequently these units operate by mechanical action alone and dispense product using the principles encountered above; suction of product as a result of an internal vacuum which is created through the flow of water past an orifice. A typical installation is wall mounted with a single hose connected to the city water input line, and contains from 1 to 5 separate dedicated hoses capable of dispensing several products. Adjusting the orifice diameter at the end of each dispensing hose, results in dilutions varying from 1:256 to 1:20.
To maintain control in small hospitals and nursing homes, 1 to 2 gallon of end use solutions are prepared and then transferred into smaller, trigger sprayer type dispensers which can easily be used by the house keeping staff. Critical areas, such as operating rooms which require high level sanitation, use specialized computer assisted dosing and rinsing equipment.

Aside from the routine clean up and sanitization of food contact surfaces and food preparation utensils, the bulk of the cleaning and sanitization in restaurants is in mechanical ware washing. In small restaurants, the dish washing product is usually a powder manually fed into the machine and also provides a source of available chlorine for sanitization. Sufficient product, whether or not needed for the soils encountered must be used in order to provide a residual available chlorine level of 100-200 ppm; a level which is required under most municipal health codes.
In restaurants serving a large number of meals daily, it becomes more economical to meter product into the ware washing equipment via rotary pumps which accurately dispense the quantity of chemical required. The larger ware washing units are equipped with a 3 head rotary pump dispensing unit and each pump is calibrated according to the amount of chemical dispensed per rotation of the pump and the number of rotations per minute. Once properly adjusted, detergent, rinse aid and sanitizer can be accurately dosed at the different required concentrations.


AQUAOX Systems produce onsite cleaning and antimicrobial liquids. Through ancillary equipment, these cleaning and antimicrobial liquids are automatically delivered throughout the facility. Users of the AQUAOX System, will receive these liquids by opening designated color-coded faucets installed throughout the facility.

These onsite produced cleaners (NaOH) and sanitizers (HOCL) are capable to replace or significantly reduce the usage of  chemical cleaners and sanitizers resulting in cost-savings and less health risks for the cleaning crew.

In my next blog, I will provide a a brief list of cleaning, sanitizing and disinfecting applications for these onsite produced liquids.  The list also include the recommended dosage and method of usage based on proven science.

For more information, please contact


February 25, 2010

When bacterial cells are exposed to a sanitizers or disinfectant, various physical structures within the cell may sustain irreversible damage. The permanent loss of a bacterial cell’s capability to reproduce is commonly referred to microbial death. In the presence of germicides, some bacteria, may only be partially damaged. A surface which is swabbed immediately after sanitization can often provide false or negative results, indicating that effective sanitization had occurred. However, depending on the degree, partially inactivated bacteria have the capacity to “heal” or regenerate within 18 to 24 hours and become viable. Such an “apparently” clean and bacteria free surface will show the presence of high levels of bacterial contamination the following day and if left unchecked, can contaminate food products which may come into contact with the surface during the normal course of food processing.
The effectiveness of a specific germicide is a function of several factors, including the number and type of microorganisms which are present on the surface being sanitized.
Some of the factors requiring consideration are whether they are the easy to kill bacteria in their vegetative state or whether they are present on the surface as highly resistant spores. A major consideration that also needs to be addressed is whether other materials such as blood, feces or organic matter are are present within the bacterial environment. These contaminants reflecting an unclean surface, can rapidly inactivate some germicides, such as hypochlorites, rendering them ineffective for their intended use.
In general however, germicides exert their effect by either attacking a specific part of the bacterial cell, or causing damage to some of its components. Germicides can fall into three classifications, based on the their method ot bacterial attack.

Germicides such as sodium hypochlorite of peroxyacetic acid (PAA), are strong oxidizing agents and can cause total destruction of the cells membrane, resulting in vital bacterial components leaking out into their surrounding environment. This process results in a true microbial death.

Some germicides, such as the quaternary ammonium compounds (quats), have the capacity to attach themselves onto specific sites on the bacterial cell membrane. They do this by virtue of the fact that the quats carry a positive electrical charge in solution and are attracted to the negatively charged portions of the bacterial membrane. The end result is that quats block the uptake of nutrients into the cell and prevent the excretion of waste products which accumulate within their structure.
In effect, the cell is both starved and internally poisoned from the accumulated wastes.

Biocides, such as phenolics, which exert their activity in this manner actually enter the cell and chemically react with certain key enzymes which support either cell growth or metabolic activities which supplies the bacteria with the energy needed for growth and multiplication. If inactivation is incomplete the injured bacteria can regenerate several hours later and recontaminate the surface.


It is presumed that viral infectivity is supressed, due to the denaturing and break down of the viral protein necessary for infection, though a reaction of that protein with two types of active oxygen present in the Water:
1.Electrolyzed Hypochlorous Acid (HOCL)
2.Hydroxyl radicals (OH)
It is widely believed that the bactericidal effect of Electrolyzed Water (HOCL-solution) against various strains of bacteria is due to the combined action of hydrogen ion concentration, oxidation-reduction-potential (ORP-reactions) and dissolved chlorine (HOCL).
First, ORP-reactions at the cell membrane damage the outer and inner membrane and inactivate the microbes defense mechanism. Then HOCL can penetrate the cell and oxidize it.

Hypochlorous Acid (HOCl, which is electrically neutral) and Hypochlorite Ions (OCl, electrically negative) will form Free Available Chlorine  (FAC) when bound together. This results in disinfection. Both substances have very distinctive behavior.

The cell wall of pathogenic microorganisms is negatively charged by nature. As such, the negatively charged Hypochlorite Ion (OCL-) can only penetrate it by the neutral Hypochlorous Acid (HOCL), rather than.

HOCL itself can penetrate slime layers, cell walls and protective layers of microorganisms and effectively kills pathogens as a result. With the aid of ORP-reaction, HOCL can even easier penetrate cell membranes. The microorganisms will either die or suffer from reproductive failures.

According to Dr. Cloete, the advantages of onsite generated HOCL has been confirmed, wherein the biocidal activity of HOCL generated onsite, is 300 times more active than Sodium Hypochlorite at the same concentration of free available chlorine. Additionally, a concentration of 2% HOCL achieved same results than 0,05% Gluterhaldehyde. Similarly, it has been shown that a 5% solution of Sodium Hypochlorite (only to be used as disinfectant) has equal results than 0.03% HOCL (which can be used as disinfectant and as sporicidal agent).

Thus, Electrolyzed Water (HOCL-Solutions) have been conclusively shown to exceed chemically derived equivalents both in low dosage effectiveness as well as physico-chemical purity.

Michel van Schaik,

Cleaning is a prerequisite for effective sanitization

February 8, 2010

Sanitization begins with an effective cleaning program. Organic deposits from food residues, such as oils, greases and proteins not only harbor bacteria but may actually prevent the sanitizer from coming into physical contact with the surface that needs to be sanitized. In addition, the presence of organic deposits may actually inactivate or reduce the effectiveness of some types of sanitizers such as hypochlorites, rendering the procedure ineffective.

In large food processing establishment, a general protocol for maintaining good hygiene works according to the following protocol: large soils and residues are initially removed by scraping or other mechanical means and usually followed by a high pressure water pre-rinse. The detergent, appropriate for the soil being removed is then applied for a specified period, usually 15 minutes, followed by a potable water rinse to flush away residual soil and detergent.

Once this process has taken place and the surface is visually clean, The sanitizer can then be applied for the specified time recommended by the manufacturer. With sanitizer applications, a further rinse with potable water is not required nor is it recommended, since there is a high probability that in doing so, might result in re-contamination of the surface with micro organisms present in the rinse water.

In the removal of soil, a detergent functions in various ways involving both physical and chemical actions. These functions do not occur separately or in any particular sequence, but in a complex and interrelated manner. For cleaning a particular type of soil, certain functions are emphasized more than others to arrive at a balanced product. Surfaces which contain oily food residues might require a product which exhibits a high level of emulsification for fatty material, whereas those contaminated with protein residues usually respond best to highly alkaline and chlorinated cleaners.

Alkaline Water (AW) produced onsite as by-product of Neutral Electrolyzed Water (NEW) is used as in significant a mild cleaning detergent and degreasing agent. AW, which consist of ~1000ppm Sodium Hydroxide (NAOH) is used prior to NEW, which consist 50-500ppm Hypochlorous Acid (HOCL) to clean and disinfect. AW is a reducing agent and chemically reduces other substances, especially by donating an electron or electrons. AW is capable of bringing about the reduction of another substance as it itself is oxidized. AW has a very low surface potential and therefore can penetrate into the smallest cell. AW is very effective in place whereas protein prevents effective sanitation.

Regardless of the product used, effective cleaning is dependent on temperature, water hardness, pH of the water used, contact time and method of detergent application. Each establishment will have its own Standard Operating Procedures (SOP), which has been worked out often by trial an error until a proper combination of the variables have found to be both efficient and cost effective.

For more information on cleaning and sanitizing using Alkaline and Electrolyzed Water, please contact

Sanitization potency of slightly acidic electrolyzed water against pure cultures of Escherichia coli and Staphylococcus aureus, in comparison with that of other food sanitizers

November 30, 2009

Abdulsudi Issa-Zachariaa, b, , , Yoshinori Kamitanid, Kazuo Moritac and Koichi Iwasakica, United Graduate School of Agricultural Sciences-Kagoshima University, Laboratory of Food Biosystems & Environment, 1-21-24 Korimoto, Kagoshima 890-0065, Japan

Department of Food Science and Technology, Sokoine University of Agriculture, P.O.Box 3006, Morogoro, Tanzania
Department of Environmental Science & Technology, Faculty of Agriculture, Kagoshima University, 1-21-24 Korimoto, Kagoshima 890-0065, Japan. Hoshizaki Electric Co.., LTD, 3-16 Minami-kan, Sakamachi Toyoake, 470-1194, Japan

Received 20 August 2009; revised 26 October 2009; accepted 7 November 2009. Available online 13 November 2009.

The sanitization potency of slightly acidic Electrolyzed Water (SAEW) on pure cultures of Staphylococcus aureus (S.aureus) and Escherichia coli (E.coli) was evaluated. The potency was compared with that of strong acidic electrolyzed water (StAEW) and sodium hypochlorite (NaOCl) solution. SAEW (ca. pH 5.8 and 21 mg/l available chlorine concentration; ACC) resulted into >5 log10CFU/ml reduction of E.coli and S.aureus after 90 s of exposure. The relative bacterial reduction potency at each exposure time was in the order StAEW>NaOCl>SAEW and increased with exploure time, with relative effect being 90 s > 60 s > 30 s. The results indicate that SAEW with low ACC and near neutral pH can potentially sanitize E.coli and S.aureus within a short period of exposure presenting a potential replacement to NaOCl solution commonly used in the food industry.

For more information, please e-mail

Electrolyzed Water

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