Ultraviolet Light Disinfection within Doctor's Offices

Risk of Contamination at the Doctor’s

Germs and disease can be spread anywhere, but public places have a higher potential to become a transmission point due to their large transient population. One of the most high-risk public places are doctor’s offices, because of the high volume of sick visitors coming in contact with many items and surfaces. Guidelines for Disease Control and Prevention in the Physician’s Office reveal that tools such as stethoscopes have been shown to be frequently contaminated with antibiotic resistant organisms such as MRSA and VRE1. Stethoscopes are used on most, if not all, patients. Additional studies have determined ballpoint pens, patient charts, tablet computers, computer keyboards and computer mice can also be contaminated with infectious agents. These items are rarely cleaned and can easily transfer disease to patients and staff due to their frequent use and tendency to be shared. In pediatric offices, there is a major concern regarding the toys kept in the waiting area, as contamination of toys by fecal coliforms, rotavirus and other pathogens has been well documented in hospitals, physician’s offices, and day care centers2. Additionally, with sick patients prone to coughing, sneezing, and vomiting, the aerosolization of germs and disease are another area of concern for transmission between patients and to staff.  Not only can infections be spread through the air, but airborne transmission can cause infections to land on surfaces besides the common touchpoints and travel greater distances.

UV Applications within a Healthcare Facility 

Ultraviolet (UV) light provides chemical-free, liquid-free disinfection proven effective against viruses, bacteria, molds, and spores. UV light can be effective on surfaces that are harder to wipe down, such as remotes, knobs, keyboards, etc. When UV light is used, the exposure can be observed through a window to safely and easily determine if critical surfaces are being adequately exposed to light. This is contrary to spray and wipe methods which are extremely difficult to determine if an area has been missed.

In the waiting and exam rooms, the Torch-Aire allows for continuous disinfection of the room’s air.  The device is quiet, effective, and safe to operate continuously throughout the day, even with patients and staff in the room.  The Torch-Aire simply pulls the room air through a UV treatment tunnel which disinfects it and returns it back into the room. Room surfaces can be disinfected by a variety of UV disinfection towers, including the Torch and Torch+.  These UV systems are able to provide a 99% reduction of many harmful organisms within 5 minutes. For areas needing special attention, the Torch-Flex and Torch Double-Flex are capable of applying UV disinfection within tight spaces and focused areas. If a permanent UV system is desired, the Flashbar can be installed in the room to provide an even simpler UV system for routine disinfection.  Components, equipment, office accessories, and even toys, can be placed in a Flashbox, or for smaller items, a Flashbox-mini.  These devices allow items to be placed inside them and quickly be exposed to UV-C light for disinfection in as little as 1 minute.

Relying on cleaners coming in nightly is not enough to provide your patients the best protection from germs that they deserve. Ultraviolet light disinfection methods provide a low cost, simple approach to address areas often unable to be properly cleaned otherwise. In order to provide the best quality of care for patients and reduce the risk of spreading germs, a clean and healthy patient environment is essential. Your patients and staff will all benefit from knowing that they are being protected while in your office. 

1. Canada, Provincial Health Services Authority, BC Centre for Disease Control. (2004). Guidelines for Infection Prevention and Control in the Physician’s Office.

2. Paediatr Child Health. 2008 May; 13(5): 408–419.  

Case Study: Decontamination of an ABSL-3 Facility and its Ductwork

A university’s ABSL-3 area was set to be renovated.  The laboratory had been used for research with tuberculosis (TB) and needed to be decontaminated before it could undergo extensive renovation. The associated ductwork also required decontamination prior to demolition of the existing exhaust system.  Removing contaminated ductwork is a complicated and difficult task, and it proved easier and more cost effective to decontaminate the ductwork along with the laboratory prior to removal of the existing ductwork. Current decontamination methods for rooms include manual spraying and wiping with chemical disinfectants or the application of formaldehyde gas, hydrogen peroxide vapor, or chlorine dioxide gas. When ductwork is also involved in the decontamination, the methods that are practical for implementation become more limited.

The manual spray/ wipe method was ruled out very quickly. Personnel must spray each and every surface with the decontaminating agent, ensure sufficient coverage with the sprayed liquid, allow the agent to remain on the surface for the specified contact time (typically 10-20 minutes), and then wipe the surface. This method seems extremely prone to human error, especially when considering the difficulty in accessing every interior surface in the ductwork. Formaldehyde gas was considered as a possible method as it is effective over a broad range of organisms, has relatively low cost, and can effectively reach applicable surfaces due to its gaseous properties. However, formaldehyde is listed as a potential carcinogen by the U.S. EPA and as carcinogenic to humans by the International Agency for Research on Cancer. It also requires neutralization and manual wiping of the potentially harmful neutralization byproduct, consisting of paraformaldehyde and/or the neutralization product. Vapor Phase Hydrogen Peroxide (VPHP) was another method evaluated. VPHP is an effective sterilant under ideal conditions but has the potential for inconsistent distribution where temperature gradients exist or where small areas (like the inside of ductwork) trap the movement of vapors and create condensation. Additionally, VPHP has been known to break down upon contact with galvanized metal such as that used in this project’s ductwork. These potential drawbacks led project leadership to seek other options. 

Chlorine dioxide gas (CD) was evaluated. It is not carcinogenic and does not leave a residue.  It has a yellowish-green color, which allows its concentration to be precisely monitored and controlled by a UV-VIS spectrophotometer.  This permits effective process control of the decontamination cycle, because concentration parameters can be established and validated.  CD has broad biological efficacy and has been approved for use as a sterilant by the US EPA.  As a gas, CD is not susceptible to temperature gradients, and CD does not condense at typical ambient temperatures or upon contact with the metals found in ductwork. As such, ClorDiSys Solutions, Inc. was selected for the project using chlorine dioxide gas.

After evacuation of all occupants, animals and disposable supplies from the area, the HVAC system was modified to allow for containment and re-circulation of CD. The decontamination process consisted of a humidification phase where steam generators were placed in the areas to raise and hold 65%-75% Rh for over of 30 minutes. Once the areas were humidified, the steam generators were shut off, and the gassing cycle was initiated. The cycle progressed until the concentration reached the target concentration of 1 mg/liter (360 PPM). This was achieved in approximately 75 minutes. At this time, the gas source was turned off, and the concentration held in the areas for a minimum of two hours, achieving a minimum exposure of 720 PPM-hrs. After the two-hour contact time, aeration was initiated by temporarily reconnecting the room exhaust duct to the building exhaust riser. The aeration continued until the CD levels were below the detection level of the concentration monitoring system. When the levels within the project area were at or below 0.1 PPM, (approximately 20 minutes) the areas were entered.  

The results of the decontamination cycle were successful and yielded a total dosage greater than 1090 ppm-hour exposure of chlorine dioxide gas.  This level is more than adequate to provide a 6-log sporicidal reduction referenced in various published sources.  Demolition of the ductwork started the next day.

ClorDiSys Solutions’ gaseous CD is the safest and most effective way to decontaminate your BSL-3 and BSL-4 laboratories, passthroughs, chambers, biological safety cabinets, HEPA filters and any other lab spaces. To learn more about our process and its applications, click here.

Top Reasons to Attend the 2019 Food Safety & Microbiology Conference

The 2019 Food Safety and Microbiology Conference is a 2.5 day event that delivers high-level problem solving sessions in order to elevate food safety programs and address emerging food safety issues. This is the third year ClorDiSys Solutions and Kornacki Microbiology Solutions is hosting the conference with the location changing each time. In 2019, we will be at the Emory Conference Center Hotel in Atlanta, Georgia from February 24th to the 27th. Here are five reasons why anyone responsible for designing and implementing food safety, HACCP, or preventive controls programs should attend:

LEARN FROM FOOD SAFETY EXPERTS & INDUSTRY LEADERS
You'll be able to meet, listen to, and learn from world class speakers with a variety of backgrounds. These industry, academic, and governmental food safety professionals will be available outside of their presentation times for introductions and additional questions. Confirmed speakers include:

• Art Liang - Senior Advisor for Food Safety, CDC
• Dina Scott - Total Quality Manager, Darden Restaurant Group
• Duane Grassmann - Corporate Hygiene Manager, Nestle USA
• Michele Sayles - Executive Director of Food Safety and Quality, Diamond Pet Food
• Dr. Francisco Diez-Gonzalez - Director of the Center for Food Safety, University of Georgia
• Melissa Calicchia - Chief Science Officer, Food Microbiological Laboratories

WORLD CLASS CONTENT
The agenda will feature a mix of regulatory information, microbiological tips and tricks, and innovative solutions in order to provide a well-rounded balance for all attendees.  Upon leaving, you'll have clear takeaways which will help improve your company operate cleaner, safer, and more efficient than ever before.

LOCATION, LOCATION, LOCATION
Get ready for some Southern hospitality, because this year’s conference is taking place at the Emory Conference Center Hotel in Atlanta. Nestled next to Hahn Woods, a peaceful 26-acre nature preserve, the hotel’s location is the ideal combination of a tranquil and convenient. When you aren’t attending our conference sessions, take advantage of the on-site amenities including in-room dining, two restaurants, fitness center, indoor pool, and outdoor fire pit. Explore nearby hiking and bike trails, historic attractions and monuments, or go shopping at Lenox Square and Phipps Plaza.

HAVE FUN WITH YOUR FOOD INDUSTRY PEERS
This Annual Conference is a lot of learning packed into a short amount of time, but you’ll also have opportunities to relax and get to know your industry peers. Don’t miss our Welcome Reception at Wisteria Lanes! Wisteria Lanes is a private, retro-styled bowling alley located at the Emory Conference Center Hotel featuring six full-service bowling lanes, a video gaming station, large screen televisions, billiard tables and shuffleboard. Admission to reception is included in your registration fee.  Outside of Sunday’s Welcome Reception and our Monday Happy Hour, there will be other opportunities for networking and getting to know your fellow attendees.

Registration is $995 per person with discounted group and government rates available. Registration can be completed at www.foodsafetycon.com or by completing this registration form. We hope to see you in February!

Liquid Chlorine Dioxide Solutions

Chlorine dioxide has been recognized as a disinfectant since the early 1900s and has been approved by the US Environmental Protection Agency (EPA) and the US Food and Drug Administration (FDA) for many applications across a variety of industries. Liquid chlorine dioxide is very versatile and can be used to wipe down surfaces, fog, pour down drains, and more. Fogging is a simple, affordable approach to decontaminate a space, but it will not penetrate as perfectly as chlorine dioxide gas into every space in a facility, but fogging can be useful dependent on your facility’s needs. Adding liquid chlorine dioxide to drains is crucial, because these hot spots harbor harmful organisms likely to spread to other areas causing a more widespread issue. Chlorine dioxide is especially effective at biofilm removal, so adding the continued use of liquid chlorine dioxide to your company’s sanitation program will dramatically reduce and prevent biofilm formation.

CSI 3000™ is an EPA-registered (#75757-2) pure chlorine dioxide concentrate. No on-site mixing or “activation” is required, just dilute from the 3000 ppm to the necessary concentration. It is easier to apply, safer to handle, and more effective than chlorine or bromine-based products. It is used to control microorganisms in food, research, production, pharmaceutical and agricultural applications.


More specialized applications include:

• Treatment of potable water for human consumption
• Treatment of ventilation systems, industrial air washers, humidifiers, and evaporative coolers
• Fruit and vegetable wash
• Process water for vegetable rinses, tanks, and lines
• Sanitizer for food contact surfaces, including bottling plants
• Treatment of incubator rooms, hatching room, and egg rooms
• Treatment for red meat including parts and organs including ready to eat meats
• Stainless Steel transfer lines, hydrocoolers, and pasteurizers
• Lube additive to control bacterial lime and odor on conveyors and chains
• Treatment of animal transport vehicles
• Disinfection of animal confinement facilities
• Treatment of agricultural storage facilities

Liquid chlorine dioxide can complement your everyday cleaning practices. To learn more about the applications and benefits, click here or call ClorDiSys at (908) 236-4100.

Use of Portable Decontamination Chambers

The Portable Chlorine Dioxide Gas Decontamination Chamber is an easily transportable, sealed chamber designed for use in any governmental, pharmaceutical, manufacturing, laboratory, research or surgical setting. It offers the ability to decontaminate small and medium sized equipment and components inside a portable unit rather than in an entire room or a large fixed chamber. The portable decontamination chamber is used in conjunction with a chlorine dioxide generator to provide a rapid and highly effective method of sterilization and transport items under aseptic conditions to a different part of your facility. It also offers a way to sterilize components within the room where they are kept to minimize the chance for cross-contamination. The CD generation equipment is also easily portable and features a sophisticated sterilant concentration monitoring system to assure a tightly controlled sterilization process that is easy to validate due to the repeatable cycle.

The portable decontamination chamber contains removable shelving inside to handle multiple or large components such as computers, electronics, medical devices, sterile products, and instruments. The chamber has HEPA filtered air intakes to keep components sterile after decontamination. It can connect to your facility’s exhaust system for direct aeration or utilize an integrated carbon scrubber to remove the gas from the chamber. Custom sizing is available to fit the facility’s needs. Decontamination time can be under 90 minutes for a 63 ft3 (1.8 m3) chamber and costs under $7 in consumables per cycle.

To learn more, visit our product page or request a portable decontamination chamber quote.

Method Comparison: Formaldehyde

Formaldehyde has many properties which make it a highly effective sterilizing agent. The earliest reports of its use as a fumigant date back to the 1880s, and it has remained the chemical of choice for laboratory fumigation for decades. Like chlorine dioxide, formaldehyde is a true gas that has excellent distribution and penetration completely filling any area it is injected into. However, to be effective, formaldehyde requires long contact times (on the order of 6-12 hours), and the gas requires a post-exposure neutralization step after the contact time is completed. This neutralization step leaves residuals which must be cleaned after the decontamination.

Formaldehyde usage may be simple and inexpensive, but concerns exist over its toxicity and carcinogenicity. In fact, the European Union has banned its use in certain applications. Formaldehyde is a toxic chemical that is classified as a Group 1 human carcinogen. Largely for these reasons, formaldehyde is being used less and less for decontamination.  Gaseous chlorine dioxide is being chosen by many facilities as a safer and more effective fumigation alternative.

Learn more here from a 2011 study that compared six different microbial fumigation methods with the goal to evaluate the biocidal efficacy of alternatives to formaldehyde.

Can You See CD?

Chlorine dioxide (CD) is a greenish-yellow gas with a chlorine-like odor recognized since the beginning of the 20th century for its disinfecting properties. At every installation and service decontamination that we have done, people are always excited to see the room or chamber filled with the yellow-green gas. The visibility confirms the fact that chlorine dioxide gas gets great distribution. It also provides a safety advantage, as the gas is recognizable inside the space, so it is visually known to be unsafe to enter.


Due to its yellow-green color, chlorine dioxide gas can be measured using a highly accurate uv-vis spectrophotometer.  The photometer shines a light through a sample of chlorine dioxide gas taken from the area being decontaminated and measures how much light was absorbed by the CD Gas.  CD Gas becomes darker in color the higher the concentration becomes, which in turn blocks more of the source light.  The photometer then converts the amount of light absorbed into a numerical value for the CD Gas concentration.  This method of concentration monitoring is highly accurate as it focuses on a specific wavelength of light, and is able to handle fluctuations in concentration rapidly compared to chemical sensors.  Measuring the concentration of gas at a single location within a space is able to accurately provide the true concentration of gas at all locations within the space. 

Learn more about the process and benefits of chlorine dioxide gas decontamination on November 13th or December 11th at our CD 101 webinar.

The Dirty Secret Of Commercial Kitchens Exposed

Guest Post written by Karoline Gore

Around 48 million illnesses and 3,000 deaths are caused every year by food contamination in the United States alone. This is quite alarming as today’s technological advancements and exposure to safe cleaning methods should drop these figures down to the bare minimum. Although sourcing meat and produce from reputable establishments is a start, one of the best places to stop the spreading of harmful bacteria is in a commercial kitchen.

Dirt Traps In Commercial Kitchens

With 50% of foodborne diseases linked to restaurants, it’s important that restaurateurs know which areas are known for causing trouble. Countertops, cutting boards and prep surfaces all need a good clean and it’s important to have designated prep areas for the different types of food. But these are obvious areas that deserve special attention. An area that doesn’t really garner that much attention is the knife block, which is said to carry as much as nine times the bacteria of a bathroom floor. Other areas worth mentioning include floor joints and grouting, loose seals on countertops, and the vegetable storage rack.

Restaurant Patrons Unknowingly Exposed

Although patrons are aware that menus are high carriers for a number of bacteria and germs, another item that reaches the table less than sanitized is a glass, particularly the rim of the glass. While crockery often gets a thorough clean with industrial equipment that uses high heat and steam to sanitize, germs get right back on the glass when staff handle the glasses for serving. Glasses are the sixth most popular place for germs to lurk and if it happens to have a slice of lemon, this figure goes up substantially. Pathogens simply move from one spot to another.

Cold Rooms And Fridges Deserve A Thorough Clean

While rotting produce and meat that’s gone beyond its use-by date are obvious targets when it comes to a good cold room cleanout, these areas require more than just a quick clean. According to The National Sanitation Foundation, there are a number of germs that lurk in these depths, making a deep clean imperative. In the vegetable department, restaurateurs can expect to find salmonella, yeast, listeria, and mold. The meat compartment may contain salmonella, E.coli, yeast, and mold.

Keeping a commercial kitchen clean is imperative for the safety of the staff and patrons. Regular hand wash and disinfectant stations, as well as a good housekeeping regime, should keep bacteria at bay.

The Fragility of Hydrogen Peroxide Vapor

In April 2018, the Medicines and Healthcare Products Regulatory Agency issued a statement regarding the sterilization of direct and indirect product contact items within isolators*.  Specifically, the organization addressed the use of hydrogen peroxide vapor (VPHP) for the sterilization of direct and indirect parts and process’ overall fragility.  The agency mentioned how VPHP can fail due to very minor occlusions, with even the fatty acids from a fingerprint are able to shield organisms from VPHP.  The position paper built on this by considering that some product contact parts (both direct and indirect) are designed in such a way that makes it difficult for hydrogen peroxide vapor to penetrate them thoroughly.  They conclude that their stance is such that hydrogen peroxide vapor cannot be used to sterilize critical items.  The MHRA then states that their expectation is that contact parts are sterilized using a robust sterilization method that meets the current requirements of Annex 1 of the EU and PIC/X GMPS for the manufacture of sterile medicinal products.  They describe a robust sterilization method as one that “reaches all of the critical surfaces in a consistent and repeatable manner.”

To read the full post,  click here.

To learn more about how chlorine dioxide gas can help accommodate this application, sign up for our upcoming webinars on Isolator Decontamination and Comparing CD Gas vs. Hydrogen Peroxide Vapor taking place over the next few weeks.

*They define indirect product contact parts as those that come into contact with items and components which do contact the product (i.e stoppers). Direct contact parts are those that the product passes through, such as pumps and filling needles.

Decontamination Services & Applications: Life Science Industry

Chlorine dioxide (CD) gas can be utilized for a multitude of applications in the lab animal and life science industry. It is non-carcinogenic, residue-free, and safer on materials than bleach, ozone, hydrogen peroxide, and common liquid chlorine dioxide solutions. CD is not affected by environmental factors such as temperature, and is not subject to dew-point or condensation issues making it a versatile decontamination agent and allowing it to stay effective in all types of environments, including both ambient and vacuum pressure. Gaseous systems provide the ability to achieve a complete distribution and thorough penetration to each and every surface, including visible and invisible cracks and crevices. Some of the more common industry applications include animal holding rooms, BSL-3 and BSL-4 labs, biological safety cabinets, passthroughs, isolators, air handling units/ductwork, micro labs, and necropsy rooms.

Entire Facility Case Study:

ClorDiSys' chlorine dioxide gas technology allows for a complete decontamination of your facility, with minimal equipment and minimal downtime. A 170,000 ft3 new university research facility was decontaminated upon completion of construction and prior to the commencement of operations. Equipment and supplies were brought into the space as well, so that they would be exposed and decontaminated concurrently. ClorDiSys was able to fumigate the facility and eliminate any organisms present while providing sporicidal kill of Biological Indicators (comprised of 1 million Bacillus atrophaeus spores) to ensure the process was successful. The entire process took two days, one day for setup and one day for decontamination and clean-up.

BSL-3 Lab Case Study:

A BSL-3 influenza laboratory undergoes a yearly decontamination using chlorine dioxide gas during a facility shutdown. All equipment is left within the space during the process, as the gas is safe on materials and will reach all surfaces within the lab. This provided a large time savings as each piece of equipment did not need to be treated individually in an autoclave or other pass-through system. Results are shown through the placement of 40 biological indicators as various locations throughout the lab. Some locations include closed drawers, inside and behind biological safety cabinets, underneath tabletop equipment, as well as easy locations such as floors, ceilings and walls.

To learn more, attend our “Life Science and Pharmaceutical Facility Decontamination Services” webinar on Thursday, October 25th, visit Booth #1903 at the AALAS National Meeting in Baltimore, or visit our website’s Applications page.

Eradication of Pinworm Eggs with Chlorine Dioxide

Pinworms are common contaminants of laboratory animal facilities. Pinworm infections can have adverse effects on behavior, growth, intestinal physiology, and immunology of experimental rodents, making effective pinworm surveillance and eradication important for many facilities. However, eradication of such infections is complicated by the ova’s ability to aerosolize and remain viable in the environment for lengthy periods. Pinworm eggs are microscopic and have been found on equipment, shelving, in dust, and in ventilation air intake ducts. The University of Tennessee at Knoxville performed a study on chlorine dioxide gas’ effect on pinworm eggs to see if it was a viable option for treating contaminated spaces.

Prior to this study, only ethylene oxide gas and dry heat had been proven to eliminate pinworm eggs.  Ethylene oxide is not used for space fumigation due to its carcinogenic and explosive properties, and it is very difficult to uniformly establish and maintain the high temperatures needed for dry heat (212° F held for 30 minutes) to be effective. In a controlled study, Syphacia spp. ova were affixed to a slide and exposed to a set concentration of chlorine dioxide gas for varying amounts of time. After being exposed to chlorine dioxide gas, the ova were placed in petri dishes, covered with a hatching medium, and incubated at 37° C for six hours. Positive control ova not exposed to chlorine dioxide gas were also processed and incubated.

The parameters to achieve a 6 log level kill of viruses, bacteria, fungi, and spores are normally 1 mg/L chlorine dioxide gas (360 parts per million or ppm) for 2 hours of exposure contact time.  This equates to a 720 ppm-hours (360 ppm x 2 hours) chlorine dioxide gas dosage.  It was found that a dosage twice as long (1440 ppm-hour) was needed in order to eliminate all viable ova from hatching. All ClO2 treatment times significantly decreased the hatching rates of the ova. Below is a table showing the results of the study: 

Exposure time	Chlorine DioxideGas Dosage	% of Syphacia, spp. ova hatched
		Treated with CD Gas	Untreated(Positive Control)
1 hour	360 ppm-hour	14%	71%
2 hours	720 ppm-hour	12%	82.5%
3 hours	1080 ppm-hour	2%	80.5%
4 hours	1440 ppm-hour	0%	83%

To learn more about gaseous chlorine dioxide's effectiveness against pinworm eggs, visit Booth #1903 at this month's AALAS National Meeting or read the complete Journal of the American Association for Laboratory Animal Science article here.

Case Study: Electron Microscope Decontamination

An electron microscope can be used to study dangerous biological organisms. Occasionally, the organism can be sucked into the internals of the microscope making it hazardous to repair with concern for the maintenance technician’s health. To mitigate these concerns, decontaminating the inside components of the microscope can be accomplished using gaseous chlorine dioxide with no adverse effect on the equipment.

The normal sterilization process is automated and consists of 5 steps:
1. Precondition: Raising of humidity to make spores susceptible to gas
2. Condition: Holding of raised humidity level for spore softening
3. Charge: Injection of gas into chamber
4. Exposure: Holding of gas concentration for the set amount of time
5. Aeration: Expulsion of gas and humidity

Some microscope manufacturers add a sixth step which is a pre-purge of the system with nitrogen. If a Pre-Purge step is used, the valves are opened and nitrogen is passed through the system.

In 2009, ClorDiSys was approached by JEOL USA as they set forth to find a suitable decontamination method for their electron microscopes. They wanted a method to decontaminate the interior chambers to protect their service workers from the pathogens being studied within. Identical sets of parts were sent for material testing against chlorine dioxide and hydrogen peroxide vapor. According to “Construction and Organization of a BSL-3 Cryo-Electron Microscopy Laboratory at UTMB” in the December 2012 Journal of Structural Biology, their early attempts to use VHP with JEOL microscopes were not successful because of unacceptable level of corrosion of some parts inside the microscope column. Some showed visible discoloration and corrosion after the level of exposure necessary for a single decontamination cycle. Chlorine dioxide gas has a lower oxidation potential than ozone, peracetic acid, bleach and hydrogen peroxide, making it scientifically less corrosive than those other decontaminating agents. Our chlorine dioxide gas was selected due to its success in the material compatibility trials and is used with the $3 million TEM.

Read more about the process and benefits of using chlorine dioxide for Electron Microscope decontamination in our application note.

Case Study: Ductwork Decontamination

Traditional sanitation procedures typically do not include air handling units or their accompanying ductwork. Chlorine dioxide gas is the only residue free fumigation method that can successfully decontaminate ductwork and HVAC systems, including HEPA housings. Being a dry process and a true gas at room temperatures, CD is able to navigate the bends and turns of the ductwork system without condensing and getting "stuck." Typically, ductwork is decontaminated along with the rooms that it handles.  On one occasion, there was only a need to use chlorine dioxide gas to decontaminate the ductwork itself.

The exhaust ductwork in the BSL-2 and BSL-3 research laboratory of a major pharmaceutical company needed to be replaced. Since the ductwork was used to exhaust biological safety cabinets (BSCs) for testing on HIV and Hepatitis C, special precautions would be required prior to its renovation. The company decided that a fumigation style decontamination should be performed, and chlorine dioxide gas was chosen due to its ability to reach all surfaces and distribute throughout the entire length of ductwork without condensing or leaving a residue. The laboratory was located on the third floor of the building and consisted of a four-room BSL-2 area and a smaller, two-room BSL-3 area. There was a total of fourteen BSCs with exhaust ductwork that required decontamination and two ceiling exhausts. One chlorine dioxide gas generator was set up, and gas injection tubing was run to one BSC in the BSL-2 area and to one BSC in the BLS-3 area. The gas was then pulled through the exhaust system on the fifth floor and down to the distribution system and then into each BSC. A total of fifteen Bacillus atrophaeus biological indicators (BIs) were placed in each BSC and the two room exhaust vents to validate the decontamination. The results of the cycle yielded a greater than 720 ppm-hr decontamination time, which is more than adequate to provide a 6-log sporicidal reduction. All biological indicators were negative after the seven-day incubation period allowing the renovation crew to work in a safe environment without having to wear personal protective equipment (PPE).

To read this case study in its entirety, click here.

Follow Your Nose: CD's Best Safety Feature

While all decontaminating agents are by nature dangerous, chlorine dioxide (CD) gas has many traits which make it the safest method available. The best safety feature with CD is that it is self-alerting.  Chlorine dioxide gas has a discernible odor at safe levels, allowing you time to shut down the system and address the situation safely if it is smelled. Other agents, such as Ethylene Oxide (EtO) and Vapor Phase Hydrogen Peroxide (VPHP), cannot be sensed until you are exposed to extremely high concentrations.  This dangerous trait is why natural gas is given a sulfur-like odor additive, to act as an alert. VPHP users (and surrounding colleagues) become aware of a harmful exposure only when coughing and choking occurs, therefore a reliance on external sensors to prevent adverse health effects is more necessary.  With CD, this need for external equipment is not as strong because of its odor.  CD has an odor threshold at or below the 8-hour Time Weighted Average (TWA), so the user is self-alerted to exposure at a low level and the reliance on external sensors is not as imperative as it is with VPHP.  This makes CD safer for both the user, and any surrounding personnel who may be working nearby.

Visit our Safety page to learn more important differences between chlorine dioxide and hydrogen peroxide.

Is Chlorine Dioxide Carcinogenic?

A major factor in choosing a decontamination method is safety. All decontamination agents are dangerous as this is their function. However, gaseous chlorine dioxide can be used more safely than other fumigation methods due to its chemical properties and safety profile. One example of this is that chlorine dioxide gas is not a carcinogen. Formaldehyde is “known to be a human carcinogen” as described by the US National Toxicology Program. Formaldehyde was once a widely used method for decontamination, but its classification as a carcinogen has limited its use and caused it to be banned by some health agencies. The ACGIH designates vapor phase hydrogen peroxide (VPHP) as an A3, Confirmed Animal Carcinogen with Unknown Relevance to Humans. Chlorine dioxide gas is not considered to be carcinogenic, with no health organization listing CD as a carcinogen of any kind. In fact, it is used to treat fruits, vegetables, poultry, and other food products. Chlorine dioxide has also been used in the treatment of drinking water since the 1920’s both domestically and internationally.

Do you have safety concerns about the use of chlorine dioxide for decontamination? Attend our CD Gas 101 webinar on September 18th to ask questions and learn more.

Biological Safety Cabinet (BSC) Decontamination

The Class III Biological Safety Cabinet (BSC) is a gas-tight enclosure designed for work with highly infectious microbiological agents and for the conduct of hazardous operations and provides maximum protection for the environment and the worker.  A Class III BSC is typically decontaminated on a periodic basis and always before filter change out and repairs. Formaldehyde and chlorine dioxide gas are the only approved decontamination methods by NSF International. However, chlorine dioxide gas provides a much quicker cycle time than formaldehyde, is not a carcinogen, and does not leave a residue.

The Tufts New England Regional Biosafety Laboratory (RBL) is dedicated to the study of existing and emerging infectious diseases, toxin mediated diseases, and medical countermeasures important to biodefense. The facility’s two main decontamination choices are vapor-phase hydrogen peroxide (VPHP) and chlorine dioxide (CD) gas. Both agents are known to be efficacious, and both are sterilants. VPHP has been used longer, and many papers have been published on the process. Some issues of concern were that VPHP condenses and, when it does, the droplets become more aggressive or concentrated. Because of the increased concentrations, it has been documented to damage painted surfaces, epoxy surfaces, and electronics. Additionally, VPHP vapors have been shown to have limited distribution and penetration abilities. CD easily penetrates and distributes into all spaces. It covers an entire room, penetrates deeply into equipment, and gets into the hard-to-reach places. Setup is simple and requires very few extras (only 1 or 2 fans and a portable humidifier). Based on the needs to decontaminate this RBL, CD gas was the best choice as it provided complete decontamination of all surfaces within the spaces and inside the Class III BSC.


The Class III BSC can be decontaminated as part of the room (by opening the gull wing door), or it can be decontaminated on its own through use of the built-in connectors. The components needed are RH probe, mix box (which contains a humidity generator), blower motor, DC/AC controller, pressure relief scrubber, and the Minidox generator. The CD gas concentration is monitored via a gas sample port. This hose is connected to the Minidox, which then, on the basis of real-time readings, activated the gas injection system as needed. The scrubber removes any CD gas during this process. A standard cycle of 5 mg/L for 30 minutes of exposure is often used for Class III BSCs. However, due to the nature of this particular facility’s work, the cycle time was extended to 45 to 60 minutes. All biological indicators (BIs) were repeatedly killed, and no issues of corrosion were evident. All components continue to remain free of any imperfections. Due to that, chlorine dioxide gas is now the method of choice for the decontamination of Class III BSCs.

To read more about Tufts New England Regional Biosafety Laboratory’s utilization of chlorine dioxide gas for both BSC and room decontamination, click here. 

The Myth of Corrosion

Chlorine dioxide (CD) is an oxidizer, as is hydrogen peroxide, ozone, bleach, and many other decontaminating agents. However, CD gas is the gentlest on materials among those options, due to its lower oxidation potential. A higher oxidation potential means it is a stronger oxidizer and more corrosive. As shown in Table 1, chlorine dioxide has an oxidation potential of 0.95V, which is lower than other commonly used oxidizing biocides. CD is not as aggressive an oxidizer (oxidation potential data) as chlorine, ozone, peracetic acid, peroxide, or bleach — and it should be non-corrosive to common materials of construction.

Table 1: Oxidation Potential of Common Biocides

While scientifically less corrosive, chlorine dioxide gas has a bad reputation due to the link with chlorine as well as the other chlorine dioxide products that lack the purity that our process uses. Other methods of generating chlorine dioxide mix an acid and a base which forms a chlorine dioxide solution which is then off-gassed to fumigate a space.  That generation method produces two acidic components, acidified sodium chlorite and chlorous acid, alongside chlorine dioxide which makes these methods more corrosive. Our method of generating pure chlorine dioxide gas is accomplished by passing a low concentration chlorine gas through a proprietary sodium chlorite cartridge to convert the chlorine gas into pure chlorine dioxide gas. This allows our process to be safe when decontaminating stainless steel, galvanized metals, anodized aluminum, epoxy surfaces, electronics, and the most common materials of construction. Typically, if water will not corrode an item, neither will our CD.

To learn more about material compatibility, click here. If you have a specific item of concern, send us some samples. We offer free material testing* to give confidence that chlorine dioxide gas will be safe on your equipment, products, components, tools, etc.

*Testing is free for small items or batches. For large items or extended testing, please call (908) 236-4100. Shipping not included.

Decontamination Chambers

A Decontamination Chamber is designed for use in any laboratory, pharmaceutical, manufacturing, research or surgical setting. It provides a rapid and highly effective method to sterilize computers, electronics, medical devices, instruments, and components at ambient temperatures. It also provides a cost-effective method to decontaminate parts, supplies, and equipment entering a “sterile” or “clean” facility without the need for a large, expensive, energy consuming sterilizer. It allows the removal of items from a dirty or BSL level area to a clean area without the concern for cross contamination.

Chlorine dioxide gas is a highly effective EPA-registered sterilant. It is a true gas which naturally fills the space it is contained within, no matter the shape or amount of items within. CD gas has more consistent kill and quicker cycles than Vapor Phase Hydrogen Peroxide (VPHP). Decontamination time can be under 1.5 hours for a 150 ft3 chamber. The chlorine dioxide process is easy to validate due to the repeatable cycle, tight process control, and highly accurate sterilant monitoring system.  A run record is produced that contains process parameters.

For many applications, a Decontamination Chamber can effectively replace a bulk autoclave inside a facility. Decontamination Chambers can save energy and money compared to bulk autoclaves in terms of steam usage, water usage, electricity usage, maintenance costs, replacement costs, cost of capital equipment, and footprint. Chlorine dioxide gas is capable of decontaminating electronics, racks, cages, HEPA filters, plastics, and the outsides of bedding and feed bags.  Autoclaves are still the best suited to decontaminate dense organic materials such as bedding and feed. As many facilities have multiple autoclaves, the easiest decision might be to implement both an autoclave and a decon chamber to fulfill all of your facility’s needs. The equipment is available in a variety of sizes including a dual door option. We also fully integrate with BetterBuilt, Lynx, Tecniplast, Girton, Schyler, Buxton Scientific, and other manufacturers.

To learn more, visit our product page or request a decontamination chamber quote.

Inactivation of Beta-Lactams

Beta-lactam antibiotics are, by definition, a class of antibiotics which contain a beta-lactam ring in their structure. They are split into various groups depending upon their base structure, with the main groups being penicillins, carbapenems, cephalosporins, and monobactams. Allergic reactions to beta-lactams can be life-threatening. Due to the large number of individuals allergic, the pharmaceutical industry explored a method for their inactivation.   This research was performed such that a contaminated area could be treated and re-used for the future production of non-beta-lactam compounds. This would allow companies to “recycle” beta-lactam facilities instead of demolishing them upon the completion of production.

Testing was conducted using chlorine dioxide gas at various concentrations and exposure times in an effort to achieve the pharmaceutical manufacturer’s required 3-log (99.9%) reduction of eight different beta-lactams on various surfaces. Nine inactivation cycles were tested, with five passing the acceptance criteria beneath U.S. Food and Drug Administration (FDA)-required 0.03 ppm residue detection level. Successful inactivation cycles which achieved a 3-log reduction of all eight beta-lactam compounds all had cumulative exposures of over 7,240 ppm-hours. Further studies validated this dosage for providing a 3-log reduction of all eight beta-lactams tested.

In 2008, a leading pharmaceutical company was looking to renovate a 33-room facility, that had been used for the production of an Imipenem-based product, into a new training facility. Because positive samples for beta-lactams were found in multiple rooms and inside the ductwork, the entire production facility along with its HVAC was to be treated. Chlorine dioxide gas was injected into 24 locations and sampled from 12 locations to ensure fast and thorough distribution.  To ensure that gas was getting into the HVAC system, the recirculation blower was bumped throughout the process. Upon completion, the area was swabbed by the pharmaceutical company. All swabs came back negative proving that no beta-lactams remained, making the treatment a success.  Since that initial facility treatment in 2008, chlorine dioxide gas has been used for this specific application at a number of other facilities worldwide.

To learn more, click here.

How Does Chlorine Dioxide React with Water?

In most cases, before a decontamination occurs, the environment undergoes a wet cleaning to remove dirt and organic material.  This residual water can present a challenge for some decontamination methods.  One example being Vapor Phase Hydrogen Peroxide (VPHP) because it dilutes and breaks down in water.  So for that method to be effective, the area must be completely dry before use.  Depending on the application, drying the environment can be a lengthy process which adds a prohibitive amount of time to the cycle.

Chlorine dioxide (CD) gas is water soluble, allowing it to maintain its sterilization efficacy within water.  Unlike chlorine, CD gas does not form hydrochloric acid and maintains a neutral pH. In wet environments, chlorine dioxide can decontaminate any remaining water as well as the surfaces beneath.  This eliminates the need to wait until the environment is completely dry before decontamination occurs, in turn, decreasing the overall downtime.

One application where this has a real world effect is within decontamination chambers.  The use of decontamination chambers is becoming more prevalent within research facilities and clean rooms.  Within vivaria where space is extremely valuable, these chambers are sometimes included as part of a dual-use rack washer/decontamination chamber unit.  Within this application, if the system is run as a rack washer, the amount of water at the bottom of the chamber afterwards can take hours to completely dry out.  Being CD gas is not affected by water, it can be used within a dual-use chamber immediately after a wash cycle.  This can save your facility hours of time and allow the savings in facility footprint to become a viable option.  It also allows a contaminated facility the ability to become completely decontaminated as there’s no worry for residual water rendering the process ineffective.

Amplicon Inactivation

The rapid growth of DNA sequencing in laboratories is resulting in the increased use of PCR readers.  As a result,  researchers are making advances in science and medicine, but not without new challenges. One challenge is that the integrity of the results can be affected if amplicon residues contaminate part of the PCR reader. This contamination could cause improper analysis of subsequent samples. Mitigation of this problem requires amplicons to be inactivated from all surfaces of the PCR reader, including all cracks and crevices of the equipment.

Chlorine dioxide gas cycles have been validated with multiple PCR reader manufacturers in order to clear the reader from residual amplicons which can cause inaccurate results and readings.  The validation consisted of a series of cycles with varying chlorine dioxide gas dosages that were tested to achieve an inactivation of the amplicons. The verification process also confirmed that the equipment was not corroded as a result of the treatment cycles.

ClorDiSys Solutions, Inc performs amplicon inactivation work as part of its contract sterilization and decontamination services.  Two manufacturers of PCR readers have their customers send equipment to our facility before having it returned to the manufacturer for maintenance and repair.  At our facility, our contract sterilization team treats the units to eliminate any residual amplicons and blood-borne pathogens. This treatment allows the equipment to be safely handled by the manufacturers' maintenance department.

For more information, please read our Application Note on Amplicon Inactivation here.

Case Study: The Musculoskeletal Transplant Foundation (MTF) Isolator

The Musculoskeletal Transplant Foundation (MTF) is the nation’s leading tissue bank. MTF designed and validated the use of isolators in the production of DBX Demineralized Bone Matrix (DBX) putty. DBX Putty is the combination of demineralized bone and sodium hyaluronate for use during surgical application. Since the DBX putty is introduced into the body, it must be produced and packaged under aseptic conditions and procedures. Aseptic technique refers to efforts to maintain a sterile field during a procedure to prevent infection. In order to maintain the highest aseptic techniques, it was decided to move the DBX Putty process to isolators for their ease of use in cleaning and decontamination. The process whether conducted in a clean room, biological safety cabinet, or an isolator is largely the same with the exception of the decontamination cycle.

In order for this process to be economically feasible, the decontamination cycle had to take less than 2 hours.  If the decontamination time exceeded 2 hours, then it would not be cost effective enough to warrant the change from clean room processing to isolation processing. The choice was between vapor phase hydrogen peroxide and chlorine dioxide gas. Both methods are registered with the US-EPA as sterilants, and both have been used in clean room environments and in isolators. The VPHP process produced varying amounts of condensation with potential for poor distribution and penetration abilities into gaps and small openings. Based on these limitations, chlorine dioxide, a true gas at room temperatures, was chosen due to its fast cycle times and evidence of its effectiveness.  With the reduced cycle times, MTF’s decision to move forward with isolators became feasible. The isolators eliminated the need for using 2.5 ISO 4 clean rooms and provided true aseptic processing.  The chlorine dioxide gas generator and isolators worked together to provide a simple and seamless systems integration.

To learn more about the Musculoskeletal Transplant Foundation’s selection, design, and validation of isolators for aseptic processing with chlorine dioxide gas, read Nick Barbu and Robert Zwick’s article in Pharmaceutical Engineering here.

Material Compatibility - Electronics

Material compatibility remains one of the largest question marks for those looking to use chlorine dioxide gas, and there’s a lot of conflicting information on the topic.  Chlorine dioxide gas cannot be stored and shipped, so it must be generated at the point of use.  The method of generation, and its resulting purity, has a great impact on the material compatibility of the chlorine dioxide gas product being used.  One of the first large scale decontamination projects utilizing chlorine dioxide gas was the oft referenced Hart Senate Building decon performed in November 2001.   It was performed by a company who previously used its CD gas technology for controlling odors in oil wells. As material compatibility was never an issue in this previous application, they used a less refined process of generation which contained acidic byproducts. When used in the Hart Senate Building, some material issues and corrosion occurred. ClorDiSys was established after this, and our chlorine dioxide gas is generated by passing a low concentration chlorine gas through a proprietary sodium chlorite cartridge to convert the chlorine gas into pure chlorine dioxide gas. Our process does not leave a residue and does not require any additional clean up once the gas has left the space.

ClorDiSys has done studies with electronics and found that they stand up well after multiple exposures. Computers have been exposed to the gas for over 25 cycles and have been fully functioning afterward. In fact, chlorine dioxide gas was chosen to decontaminate the inner chambers of a $3,000,000 Transmission Electron Microscope over hydrogen peroxide vapor because of its superior material compatibility as proven through manufacturer testing. The US Environmental Protection Agency (EPA) commissioned a study exposing computers to chlorine dioxide and hydrogen peroxide over the course of 6 months. Below are the test results showing chlorine dioxide had the lowest amount of failures.

Not all chlorine dioxide gas products are the same, and we understand the hesitation considering some of the information available regarding corrosion.  That’s why we offer free* material testing to give confidence that our chlorine dioxide gas will be safe on your materials and sensitive items.

* Testing is free for a reasonable amount of items.  Shipping not included

Ultraviolet Light in HVAC Systems

Mold, mildew, and dangerous diseases, such as Anthrax, Influenza, Measles, Smallpox, and Tuberculosis, are often spread through airborne transmission. Mold spores easily disperse, wreaking havoc in the new environments they land upon. A solution to continuously combat harmful organisms is the introduction of ultraviolet light disinfection. Ultraviolet light is divided into UV-A, UV-B and UV-C rays. It is the wavelengths in the UV-C spectrum, specifically 265 nm, that offers the greatest germicidal potential.  When a microorganism is exposed, the nuclei of the cells are altered due to photolytic processes. This process prevents further replication and causes cell death.

Ultraviolet light disinfection systems can be placed directly within HVAC ducts to both eliminate and prevent mold, mildew, and other organisms from forming and spreading.  Unlike HEPA filters that solely trap organisms, allowing them to flourish and possibly be re-released into the environment, UV-C kills organisms, eliminating that risk. Placing UV-C disinfection units within the HVAC system provides a continuous disinfection cycle with no harmful effect to anyone present in the space.  Units can be placed in the supply and the return to maximize the benefits.  Units placed in the return ducts have an even greater benefit, because the slower air velocity allows for additional exposure time. Ultraviolet light disinfection is an easy, hands-off, chemical-free way to reduce the risk of mold and mildew from developing and the spread of disease causing airborne organisms.


Attend the upcoming UV Light for Healthcare webinar on July 19th and UV Light for the Life Science and Pharmaceutical Industries on August 7th to learn more.

Can Chlorine Dioxide be used with Organic Foods?

ClorDiSys is occasionally asked if chlorine dioxide can be used in organic foods or in organic processing facilities. The short answer is yes.  More specifically, according to 7 CFR part 205, SUBCHAPTER M—ORGANIC FOODS PRODUCTION ACT PROVISIONS, the use of chlorine dioxide is allowed, but it comes with some restrictions. Its use is permitted for Livestock Management Tools and Production Aids, for Processing Sanitizers and Cleaners, and for Crop Management Tools and Production Aids. The common restriction across all three applications is the residual chlorine levels in any final rinse water or water in direct contact with food products or animals. The water cannot exceed the maximum residual disinfectant limit under the Safe Drinking Water Act (0.8 mg/L or 800 ppb). Reference the label of the product you are using to establish proper use corresponding with such restrictions. Visit the websites below for additional information to see if your organic operation qualifies for chlorine dioxide usage.

REFERENCES

• Organic Materials Review Institute, https://www.omri.org/generic-material/chlorine-dioxide

• Title 7 Agriculture → Subtitle B → Chapter I → Subchapter M → Part 205—NATIONAL ORGANIC PROGRAM https://www.gpo.gov/fdsys/granule/CFR-2011-title7-vol3/CFR-2011-title7-vol3-part205/content-detail.html

Case Study: Decontamination of Tented Equipment or Area

Food production facilities are facing greater scrutiny from both the public and the government to provide safe foods. Advances in environmental monitoring and microbial sampling have brought to light the shortcomings of the food industry’s sanitation methods. While there are many reasons for recurring contamination by a persistent pathogen, insufficient cleaning and decontamination is the most common. ClorDiSys Decontamination Services can be utilized for a variety of applications within the food industry from tented pieces of equipment up to entire facilities. Tenting an area is an application that we’re seeing more of lately, especially in facilities that have more of an open design and floor plan.

One example of this application is when our service team decontaminated a confectionery facility’s roaster. The roaster had caught fire and was extinguished by the fire department.  Worried the water used to put out the fire contained organisms which could contaminate their production line, this company wanted to clean the equipment before production started again.  Some of the equipment’s interior was not easily accessible for the in-house sanitation team, so once the majority of cocoa powder was removed, the company opted to decontaminate with chlorine dioxide gas. That equipment was tented and fumigated, as the rest of the room was not deemed a concern. The setup and decontamination of the roughly 8,000 ft3 space took place in 1 day and successfully provided a 6-log sporicidal reduction of all surfaces within the equipment.

ClorDiSys’ Decontamination Services can be arranged for contamination response or preventive control needs. Visit our team at booth #609 at the IAFP Annual Meeting in Salt Lake City July 8-11th to learn more!

Case Study: Used Equipment Decontamination

Our Decontamination Service Team recently completed a decontamination of a used bacon slicing line for a food company.  Because it was a used piece of equipment, the company did not want to bring it into the facility without being decontaminated first. This was not only to preserve the current sterility of their production area, but also to ensure safe food production once the line was in use. The slicing line was placed within a trailer which provided a sealed chamber for safe decontamination. 10 biological indicators were placed within the trailer and equipment in order to show that a 6-log reduction had been achieved. Once the trailer was sealed, the decontamination started.  The entire setup and decontamination took 4 hours from start to finish, when it was safe to open the trailer and bring the equipment into the production area. All biological indicators came back negative for growth verifying that the decontamination was successful. Production was able to start on the bacon slicing line shortly after being installed within the production area, and the company has been safely producing food since.

Contaminated piece of equipment in your facility? Call ClorDiSys at (908) 236-4100 or email the Decontamination Service Team at service@clordisys.com.

Continuous vs. Pulsed UV-C

Not all ultraviolet disinfection is alike. In fact, not all ultraviolet light is alike. Ultraviolet light is divided into UV-A, UV-B, and UV-C rays. It is the wavelengths in the UV-C spectrum which offer the greatest germicidal potential. Some UV disinfection systems, like xenon pulse UV, use the full spectrum of ultraviolet light to disperse germ-killing energy. It is claimed that the xenon pulse is a more effective way to kill harmful bacteria because of its similarities to punching a wall, more punches will weaken it better than one. However, light is not a fist. It is a form of energy, and continual energy is more effective than turning it on and turning it off. Additionally, bulbs generating UV-A, UV-B, and UV-C wavelengths are inherently less effective in disinfection than continuous UV-C.

The US Veterans Administration commissioned an infection prevention research team led by Curtis Donskey, M.D., to conduct an independent study of continuous ultraviolet disinfection versus xenon pulse UV disinfection. The study tested a continuous UV-C robot which was run for the same length of time from the same point in the room as a pulsed xenon (PU-UV) unit.  The results showed surprisingly low pathogen kill rates for the pulsed xenon device, about .5 log for both C.diff and VRE, even as close as 4 feet.  The continuous UV-C robot demonstrated a much higher CFU reduction for the pathogens C. difficile, MRSA and VRE.  The study states, “PX-UV was less effective than continuous UV-C in reducing pathogen recovery on glass slides with a 10-minute exposure time in similar hospital rooms” and “the UV-C device achieved significantly greater log10 CFU reductions than the PX-UV device”. Not only did the continuous UV-C robot in the study show much stronger disinfectant results, but that it was not run for its entire cycle time. The study calls attention to the dangers of bold claims and trying to complete a disinfectant procedure too quickly.

Chart from VA Donskey study: Study results showing log reductions achieved by a UV-C and pulsed xenon devices
when run for the same time (10 min.) at the same distance from glass microscope slides (4 ft).
(PRNewsFoto/Infection Prevention Technologies)

To read more on the comparison of these two technologies, click here.

Decontamination of Spiral Freezers

The biggest challenge in successfully cleaning spiral freezers is trying to reach all the surfaces.  Spiral freezers are constructed with minimal clearances, making it hard to use traditional cleaning techniques such as the spraying of liquid chemicals.  The interior is too tight to maneuver cleaning equipment properly and operate it effectively.  Cleaning every nook and cranny inside of a spiral freezer is a very difficult task when taking into consideration all of the internal components, all of the hard to reach crevices, the difficulty in maintaining the correct contact time of the chemical being used, and the difficulty in the agent reaching all surfaces.

Chlorine dioxide gas has been proven effective at eliminating listeria from within spiral and tunnel freezers. ClorDiSys’ chlorine dioxide gas is made using a proprietary generation method and is registered with the US EPA as a sterilant providing a 6-log (99.9999%) reduction of all viruses, bacteria, fungi, molds and spores. As a true gas, chlorine dioxide naturally fills the spiral freezer evenly and completely, and with a molecule size smaller than the smallest organism, there’s no surface that is safe for pathogens to hide. Gaseous CD is the only decontaminant that penetrates water and decontaminates both the water and the surface beneath, which is important for spiral freezers that typically have condensation issues.

One facility which produced frozen sausages had a persistent listeria problem, resulting in consistent positive swabs. After one treatment with chlorine dioxide gas, the facility was able to eclipse 16 weeks without a single positive swab after testing 2-3 times per day. CD gas decontamination has been written into a quarterly preventive maintenance schedule.

Attend our Food Facility Decontamination Services webinar on June 7^th to learn more or stop by Booth #10 at the North American Food Safety and Quality 2018 on June 5-6^th to further discuss.

How Ultraviolet Light Help Prevent The Spread Of Ebola

While combating the highly infectious Ebola virus disease (EVD) outbreak in West Africa, aid workers and other visitors have been inadvertently exposed and contracting the virus. In 2014, a number of infected individuals were evacuated from Africa and returned to the United States for treatment. The Nebraska Biocontainment Unit (NBU) was one of the several receiving hospitals for these patients. The NBU and Omaha Fire Department’s emergency medical services coordinated patient transportation from the airport to the high-level isolation unit. Following patient admission into this unit, biocontainment staff members relocated the ambulance to an isolated, controlled-access area to be decontaminated. All surfaces in the cab and patient compartment were thoroughly wiped with bleach solution. Then, as a final disinfection step, the back of the ambulance was exposed to ultraviolet light.

Ultraviolet light is a specific part of the electromagnetic spectrum of light that offers bactericidal effects. It is the wavelengths in the UV-C spectrum, which offer the greatest germicidal potential. UV-C provides a dry, chemical-free, and residue-free method of disinfection effective against bacteria, viruses, fungi and spores. For this reason, ultraviolet light disinfection was not only used in the ambulances, but as the final step in decontaminating medical equipment, patients’ rooms, and bathrooms after patients were discharged. Acknowledging the known limitations that UV-C only disinfects the areas light can reach, the Nebraska Biocontainment Unit used four ClorDiSys Torch systems in tandem to ensure the proper exposure was achieved to inactivate the Ebola virus.

Read more about the effective use of ultraviolet lightdisinfection against Ebola here.

Learn more about ClorDiSys Solutions’ Torch here.

How Often You Should Schedule Preventative Decontamination

Over the past couple of years, we've noticed a shift within our decontamination services projects.  At first, all projects were in response to active contaminations.  More recently however, we've noticed a shift as more of our decontamination service projects have been scheduled as part of a preventive sanitation effort, aimed at providing a more thorough kill than traditional sanitation can achieve.  One of the more frequent questions we get when discussing preventive decontamination is, 'how often should we decontaminate?'  It's a great question, and its one that doesn't have a simple answer as every situation is different.

When discussing the frequency and scheduling of preventive decontamination, the best first step is to review your environmental monitoring data.  Sometimes, there's a trend within the data that can help guide the process along.  In these situations, we would propose to undercut that trend so that the decontamination takes place before the next positive "is expected."

Example:
A processing area shows positive environmental monitoring swabs approximately every 6-8 months. 

Proposed Preventive Schedule:
Decontamination every 5 months

For areas where there is no easy to determine a trend in positive environmental swabs, another approach must be taken.  In these situations, the following factors should be considered:

• The environment itself (a room, spiral freezer, entire processing area, etc...)
• The risk level of the product and environment (raw meat vs. canned foods vs. produce vs...)
• Historical environmental monitoring data
• Downtime / Availability of the space (24/7 production, 24/5 production, yearly shutdown, etc...)

We've seen preventive decontamination schedules ranging from daily (for the decontamination of brushes and dry cleaning tools within a Decon Chamber) to quarterly (Spiral Freezers and Aseptic Fill Rooms) to Annual (Processing Areas and Production Rooms).

If you're interested in learning more about Preventive Decontamination as a supplement to your sanitation program, contact us at 908-236-4100 or visit www.clordisys.com/foodsafetyapp