Biosecurity Design: Air Handling, Surface Treatments Play Key Roles in Food Industry Safety, Health

This article is based on a presentation by Donald Hamm, senior vice president of sales, Zirconia, Inc., Tukwila, WA, (206-219-9236)/, given online at the 2020 International Association of Operative Millers’ (IAOM) All-District Virtual Conference and Expo, Sept. 15-17, 2020.

Hamm is a technologist who has brought more than 100 new products into the infrastructure and construction markets over nearly 20 years. Over the last decade, he specifically has focused on new technologies in the concrete market that improve the quality of construction and control biological hazards at the same time, advancing the next evolution of biosecurity in the food industry.

He is a recognized thought-leader in food safety who has led many discussions on this topic in the food industry.

He also is a member of the Construction Specifications Institute (CSI), an organization that puts architects, engineers, designers, builders, building owners, and everybody involved in instruction to look at better building practices and building methods.

IAOM members who registered and paid for the virtual conference still can view the presentation using their provided link, username, and password.

The article contains an excerpt of some key highlights of comments related to this presentation, which have been edited for clarity and brevity.

Trying to maintain any food facility in a manner that produces safe and healthy products consistently can be a demanding challenge, even under the best of circumstances. However, there are nevertheless common-sense approaches and state-of-the-art technologies to succeed in operating a biosecure facility.

Whether it involves a virus or bacteria, essentially these pathogens first attach to some surface, then grow, multiply, and perhaps even mutate, and start to spread easily when people touch the infected surfaces that now serve as hosts.

At this point, the pathogen is becoming more mobile and airborne inside the working environment and can create health and safety issues.

Add to that the serious challenge of containing and controlling the COVID-19 virus, and the reality sets in quickly that the broader view of health and safety involves more than the traditional things such as equipment operation, fall, fire, or dust hazards.

Those traditional topics and others are important; however, in today’s management climate, there also is the need to place more emphasis on maintaining a biosecure facility that continues to promote and enhance the health and safety of the employees but also in the products the facility produces.

This focus on biosecurity also has translated into examining more closely key aspects of building design and how certain technologies can be utilized to create a safer environment.

Transition Space

When discussing building design, one key factor to keep in mind involves transition space.

For example, how do you go from the outdoor environment, where controlling biological challenges can be difficult, to an area in the facility that needs to stay clean?

In this case, the necessary transition space can be achieved with a high-end clean room, such as an International Organization for Standardization (ISO) 1 clean room capable of rigorous air filtration.

(Editor’s note: In the case of clean rooms, the ISO 1 standard specifies the capability of handling 500 to 750 air changes per hour. The standard requires the filtering of particulates smaller than a speck of dust.)

This is one reason why it’s important to provide accommodations where employees can change out of dirty clothes to prevent any possible microbiological contamination in the food production areas.

In short, employees need designated areas where the potential for contamination can be isolated and contained.

Air Handling and Treatment

Building design also plays a prominent role in the ability to maintain airflow conditions that enhance food safety.

Controlling airflow helps minimize the risk of having airborne bacteria infiltrate the facility.

This is a key reason why understanding the impacts of positive and negative pressure zones inside the facility are so important.

Facility design factors focus on ways to minimize the entry of airborne bacteria into a facility and its heating, ventilation, and air-conditioning (HVAC) system.

The key goal is to mechanically maneuver any possible contaminated outside air so that at the point of entry into a facility, it can be treated effectively to make it harmless.

This air–whether being cooled or heated–needs to pass through different filtration and treatment systems, so that clean air can be recirculated into the rooms.

Some of the more notable air treatment methods include:

• High-efficiency filters. Air handling systems using high-efficiency particulate air (HEPA) filters can be very effective in filtering incoming air and keeping it clean.

• Ionization. As a standalone process, ionization basically is charging the air electrically, which causes any particulates and microbes to cling to collection surfaces before entering a facility. This process also helps reduce odors.

The collection plates can be washed and reused periodically, as they become laden with contaminates.

This equipment may not kill or contain the bacteria completely; however, the contaminants are isolated and kept out of the airflow that enters the working environment.

Some equipment might even utilize in combination both high-end filtration systems and ionization to clean the incoming airflow.

• Ultraviolet radiation. Using ultraviolet (UV) radiation for germicidal purposes is very commonplace in the healthcare industries, as well as in various food processing situations where sterilization may be required.

In addition, UV air purifiers are designed to use short-wave ultraviolet light (also known as UV-C) to inactivate airborne pathogens and microorganisms such as mold, bacteria, and viruses.

However, stringent safety precautions must be followed to protect employees from any exposure to UV radiation.

• Peroxide generation. Kansas State University (KSU) has been using peroxide generation as a way to treat and clean the air and actively get rid of bacteria and viruses, including COVID-19.

Last year, for example, KSU installed dry hydrogen peroxide machines in residence halls and other buildings as part of its effort to mitigate the spread of the coronavirus.

The wall-mounted machines are the size of a large fan and constantly emit dry hydrogen peroxide, a gas that kills microbes in the air.

These peroxide generators produce an airborne sanitizer that sanitizes the living microorganisms in the air as well as on surfaces.

Examining Surfaces

Plastics like polyvinyl chloride (PVC), fiberglass-reinforced panels, and fiber-reinforced polymer (FRP) metal are non-porous materials with smooth surfaces.

While such surfaces don’t harbor or promote the growth of potential pathogens or organisms, they still must be cleaned properly, so that any possible contamination can be reduced.

In contrast, concrete masonry unit (CMU) or block walls, as well as concrete floors, can pose problems due to their high degree of porosity that serves as a substrate for pathogens to prosper.

For example, more than 10% of the surface area in typical concrete is made up of voids or pores. Almost like a sponge, these voids are going to capture and retain water or other foreign material and result in creating an ideal habitat where pathogens can thrive.

Surface Treatments

While regular concrete surfaces may not be very easy to clean, they can be treated with special coatings to make that possible. A few examples include:

• Epoxies. Epoxy coatings are often applied to concrete to produce a smoother surface that makes cleaning easier and more effective. While epoxy coatings don’t chemically react with the concrete, they also don’t kill any surface pathogens. Regular cleaning still is required so that any potential pathogens on the concrete surface are eliminated and don’t come into contact with personnel and transferred to other sensitive areas within the facility.

• Urethane mortar coatings. For a longer-lasting and smoother surface, urethane mortar coatings offer great bonding ability and stand up well to frequent cleaning with various chemicals and can perform well under wide temperature fluctuations.

• Ceramic surface treatment. A ceramic treatment sealant, which is applied as a geopolymer slurry and cures at room temperature, eliminates porosity and helps to stabilize the surface chemistry.

Unlike other coatings, a ceramic surface treatment bonds chemically with the concrete and forms an entirely new surface layer that also is scratch-resistant.

This treatment forms a very hard top surface layer that’s made up of zirconia, silicate, alumina silicate, and carbon fiber. These extremely durable materials adhere very strongly to the cement.

Essentially, it becomes a new biologically impervious, nonporous, and biosecure surface.

Salts, foodstuffs, gum, or carbonic acid can’t penetrate this surface. It becomes a safer and more durable environment that helps eliminate bacteria, viruses, and fungi or prevent them from getting a foothold.

This treatment offers a four-level defense system.

1. The first clean surface layer actually is providing a nano- or molecular-level of protection against surface microbes.

2. The second level of defense is a completely nonporous, inorganic glass layer that protects against any foreign material or pathogens from penetrating the surface.

3. The third level of defense stems from the chemistry and the product itself. Just like the bimetallic qualities of copper and silver, which can kill bacteria and other organisms, zirconia offers the same capability and even delivers a stronger reaction.

4. The fourth level of defense entails what is known as a photocatalytic layer in which when it is hit with various spectrums of UV light, such as A or C wavelength, a chemical reaction occurs with the air moisture helping to clean and sterilize the surface.

Even in surrogate testing with the ceramic surface treatment, results have shown a 99.99% kill rate on E-coli, Methicillin-resistant Staphylococcus aureus (MRSA), and Salmonella.

This technology also has been tested successfully on other bacteria, viruses, fungi, algae, and yeast.

Additional Testing

Presently, Zirconia is testing this technology on the Covid-19 virus, which is expected to pass due to the prior success with killing other pathogens by breaking up the cell membranes to release the RNA, so that it can’t reproduce.

(Editor’s note: The principal role of ribonucleic acid (RNA), a nucleic acid present in all living cells, is to act as a messenger carrying instructions from deoxyribonucleic acid (DNA) for controlling the synthesis of proteins, although in some viruses, the RNA rather than DNA carries the genetic information.)

Overall, the ceramic surface treatment provides a superior and very cleanable sealed surface and is extremely durable under the most challenging environments.

Karl Ohm, contributing editor

Editor’s note: For further reading, see:

• Putting Pathogens in Check, First Quarter 2021 Milling Journal, pages 14-20.

• Wheat Flour Safety, Third Quarter 2020 Milling Journal, pages 14-18.

• Guarding Against Foodborne Illness, Dr. Karen Neil, senior epidemiologist, Centers for Disease Control and Prevention (CDC), Atlanta, GA, who gave the keynote address at the 122nd annual IAOM Conference and Expo, April 11, 2018 in Atlanta. See Second Quarter 2018 Milling Journal, pages 20-22.

• Controlling Pathogens in Wheat, by former Milling Journal Editor Karl Ohm in the Third Quarter 2018 Milling Journal, pages 12-23.

• Pathogen Environmental Monitoring, Second Quarter 2015 Milling Journal, pages 40-43.

• Enhancing Food Safety, Fourth Quarter 2014 Milling Journal, pages 22-30.

• Sanitary Design, Fourth Quarter 2012 Milling Journal, pages 4-8.

• Ozone Status Report, First Quarter 2012 Milling Journal, pages 42-44.

• Sanitary Design in Facilities, Third Quarter 2011 Milling Journal, pages 42-44.

All of the articles can be accessed online by going to

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