By Bob Baker

The food industry has committed hundreds of millions of dollars in capital expenditures and increased operating cost - specifically to the cause of improved food safety and quality. The industry takes food safety responsibilities very seriously. Product quality does not happen by chance. The industry's ongoing commitment to excellence and a willingness to invest in new technologies and procedures reflects the principles outlined in HACCP (Hazard Analysis Critical Control Points).

HACCP is a science-based system, monitored by USDA, which focuses on key areas of the food production process that must be controlled in order to prevent food safety problems. The Food Safety and Inspection Service (FSIS) completed the regulation on July 25, 1996. The new rule was in response to foodborne illness outbreaks and requires meat, poultry and egg product plants to implement HACCP systems as a means of controlling their processes to prevent microbial contamination. This regulation represented a significant step in modernizing federal meat and poultry inspection. The first milestone in implementing the new regulation came on January 27, 1997, when all inspected establishments were required to develop and to start using Sanitation Standard Operating Procedures (SSOPs). The SSOPs describe all procedures an establishment conducts daily to prevent direct product contamination or adulteration of product(s).

One critical control point that can be difficult manage is the air inside a food processing facility. If an excess of viable organisms such as bacteria and fungi are present in the air, there is a great risk that they will settle on and contaminate surfaces and products in the facility.

Indoor Air Quality

The field of Indoor Air Quality (IAQ) is complex and rapidly changing. Considerable research is underway as to the causes and correction of IAQ problems. Although observations throughout history have noted that poor indoor air can greatly affect health, it was not seen as serious compared to other deadly threats to humanity. Medical science throughout history has concentrated its research and treatment resources on such scourges as the plague, malaria, TB, heart disease, cancer, and even problems caused by outdoor air pollution. Professionals viewed discomforts caused by poor indoor air quality as trivial compared to other maladies.

That all changed in 1976 when 29 American Legionnaires died because of a mysterious illness acquired while attending a convention at the Bellevue Stratford Hotel in Philadelphia. The deadly bacterial infection, duly labeled Legionnaire's Disease, focused attention on indoor air quality as a major issue. Once people began to study the impact of poor indoor air quality, they noticed three facts: a) people were affected by the quality of indoor air; b) poor air quality often resulted in debilitating and/or life threatening ailments; c) buildings with seemingly adequate supplies of outside air could have air quality problems. IAQ arrived as a separate and important science.

By 1990, there was broad acceptance that IAQ was a long-term problem that would require significant attention and resources to bring under control. Influential industry organizations and government agencies began to respond to this new challenge. ASHRAE revised ventilation standard 62 (published in 1989). ASTM began developing test methods for indoor contamination. EPA published a manual entitled Building Air Quality, to help building owners understand the problem and start to develop solutions. Both the Centers for Disease Control and the National Institute for Safety and Health began research projects. On the federal level, activity led to the decision by OSHA to propose a new standard on Indoor Air Quality for employers on April 5, 1994.

What Causes Poor IAQ?

We could attempt to define clean air in terms of chemical gases, suspended particles, and biological content. But, that would probably be of little use to most. Ask for an example of clean air and many people will mention the outdoor air on a spring morning following a rain shower. This example illustrates several facts we have learned about what makes air clean:

Free of particulate matter - Falling rain removes dust from the air and leaves it free of particulates. Water can be a very efficient filter. Unfortunately, water also can support the growth of bacteria and fungus. Consequently, we do not normally use water as a filter indoors. Not only would it be more complicated to handle than a panel filter, it might lead to serious microbial contamination.

Low microorganism count - Lightening generated by electrical storms produces large amounts of ozone. Ozone is a very powerful disinfectant. That is, it has the power to destroy bacteria, mold and fungus. These microorganisms contribute significantly to poor indoor air quality. Microorganisms either grow in, or are carried by, HVAC systems where conditions are often ideal for rapid and uncontrolled growth. As a result, they become highly concentrated to a level where they overcome our natural resistance and cause illnesses ranging from mild discomfort to serious illnesses. Unfortunately, in indoor environments, ozone is also a contaminate that can harm human lung tissue. Ozone is a toxic substance that can offset any benefit provided by the cleaner air.

Rapid air changes - The breeze that accompanies a storm is like a mechanical ventilation system that constantly provides a supply of fresh air. This fresh air prevents the buildup of contamination to a point where it can cause harm and discomfort. Without that change of air, odors, gases, and chemical residues can build up to the point where they cause discomfort (or, in high concentration, harm).

It seems logical, therefore, if we can control the level of particulates in the air, including microorganisms and provide sufficient fresh air inside, we will have an acceptable indoor environment. The balance of this document will deal with each of these areas and provide a simple practical plan for a dramatic increase in indoor air quality in most situations.

Particulates

Effective control of particulates is the first step in providing an acceptable level of indoor air quality. Air borne particles can be a source of problems. Many of the bits of dust and debris floating in the air directly cause illnesses or discomfort in humans. Most people have heard of and seen magnified photos of fearsome looking dust mites. These small insects cause allergic reactions in many and can harbor disease-causing bacteria. But these are just the beginning. Bacterial and fungal spores, toxic or irritating substances, and chemical residues are just some of the components of the dust found in room air. These contaminates cause discomfort and may be potentially dangerous to building occupants. The danger becomes greater the higher the concentration and the longer the exposure. Particles also have undesirable indirect effects. Many particles are organic in makeup and thus serve as a food source for microorganisms. If these particles accumulate in a HVAC system, they may contribute to a rapid growth of microorganisms on surfaces in the system. Consequently, when air moves over growth sites it dislodges particles and distributes them to the conditioned space and occupants. Also, build up of microorganisms on heat exchange surfaces can also drastically reduce heat transfer efficiency. This will increase operating costs and may reduce system efficiency.

Buildings with properly designed and maintained mechanical ventilation systems have a much greater potential for effective control of particulate matter. This is because the design of the supply outlets and returns allows for more thorough and efficient circulation. High volume air exchange (four or more complete air changes per hour) has the potential of reducing air borne particles even further. Unfortunately, few systems are properly operated or maintained and thus do not realize this potential.

Media

The vast majority of HVAC systems use spun-glass media or "throwaway" filters. The weave of these filters is often so loose that they trap only the very large particles in the air stream. Many believe these filters are popular because they are so inexpensive. Also, they represent a safety compromise. The operating cost and service life of a blower motor is highly dependent on the air resistance the blower has to overcome. Low efficiency spun-glass filters provide little resistance to air flow even when they have a significant dust buildup. Where system maintenance is lax and there is a high likelihood that filters may not be changed for many months (or even years), they may be the only choice. They filter out enough large particles that they provide some protection from damage to the equipment yet will not stop air flow if they are not changed at the end of their useful life. For this reason, it is important that you routinely service your systems, change filters, and inspect for potential problems.

One sound option is to utilize pleated panel filters. These provide a denser media that has removal efficiencies well above 20% yet the pleats provide an extended surface area that allows the filter to trap a much greater load of particulates before air resistance builds up to a problem level. These filters are available in most common sizes and are competitive in cost with other filtration options. They are available in thicknesses of one inch and thicker versions. You should utilize the thickest version that can be accommodated in the filter holder of the units you have. Often filter frames that previously held one inch thick filters can be modified simply by bending a tab so they will accommodate a two-inch thick filter. This is highly desirable and should be considered even if the filter frame must be replaced. Filtration performance will be dramatically better with a pleated filter at least two inches thick. Recently, very large accessory filter frames that can accommodate multiple filters and much thicker filters have come on the market. These are especially desirable in situations where specialized filters may be required to remove toxic chemicals or smoke from the air. Vendors of these products should be consulted for direction as to the proper media to utilize in different applications. Purchasing and installing these can be expensive but may be highly desirable in critical applications (food processing plants, healthcare facilities, etc.).

Leakage

An often overlooked fact is that all the air entering a HVAC system must be filtered. Where there is leakage around the filter or filter frame or the air return ducts leak, contaminated air will reach the air handler and the benefits of improved filtration will not be realized. An important task in a filtration improvement program is inspecting and testing for duct leakage and repairing the leaks found. This is very important when the leak is in a duct that passes through a non-conditioned space. The quality of air in such a space is often very poor. Thus, such a leak can introduce significant contamination into the system.

In a like manner systems that include outside air inlets for fresh air makeup must bring that air in before the filters. Outside air must be filtered before being conditioned and circulated. Many IAQ problems have been traced to contaminated outside air.

Microbial Growth

The uncontrolled growth of microorganisms has come to be identified as the major source of indoor air problems. Early studies of air quality tended to dismiss the impact of such growths. This is because these small organisms are very common in the environment. Growing organisms can be detected in some quantity on almost any surface indoors and are common in soil and even can occasionally be found in food. In small concentrations, most microorganisms are seen as relatively harmless. Unfortunately organism populations in HVAC systems are seldom small. The temperatures and moisture levels in systems support very rapid growth. Trapped dust and other particles contain a high level of organic material that serves as food and sustains that high level of growth.

In order to effectively control growth, it is necessary to understand a little about growth and how it occurs. Microorganisms are not isolated in nature. In fact, they are extremely common. They are, however, few in number in any given location. Microorganisms consist of bacteria which are actually very small animals and algae and fungi which are considered plants. The difference between algae and fungi is that algae need light to grow and fungi grow in the dark. Microorganisms are also classified as pathogenic (or disease causing) or non-pathogenic. Pathogenic types are, fortunately, less common than others. However, organisms that are not pathogenic can cause irritation or allergies in sensitive individuals, especially when they are present in large quantities. Normally, microorganisms grow at a fairly slow rate. They have relatively short life spans and so do not become highly concentrated in any given location. This is good because most organisms are not a problem in small quantities. We call concentrations of microorganisms "colonies" and single organisms "colony forming units (or CFU for short). This is because, with the right conditions, a single CFU will rapidly divide and soon form an active colony. To grow rapidly, microorganisms need moisture, food and the right temperature.

Some organisms can grow by pulling water out of the air. It is safe to assume that growth of these will speed up as relative humidity rises above 60%. This is why mold and fungi are greater problems in high humidity areas and in the summer when the average humidity is higher. When standing water is available, additional organisms will grow and growth will be much more rapid. The longer water stands without being diluted by fresh water the larger and more concentrated a colony of organisms will become. Standing water doesn't always have to be a visible puddle. Porous materials such as fabrics (carpets), insulation, and wallboard can hold enough water after being flooded because of a leak or spill that the effect on microorganism growth is the same as standing water.

An important part of a growth control strategy is to minimize the presence of water. This starts with the control of indoor relative humidity to below 60%. Often building managers will turn off HVAC systems when the facility is not being used in order to save energy. This can allow the humidity level to rise significantly and lead to uncontrolled growth. A better strategy is to shut down the supply of moist outside air during periods of low use and run the air conditioning system enough to maintain humidity at below 60%. Special control system modifications may be needed to accomplish this. Designing and installing these can provide additional income and greatly benefit your customers. A major location for standing water that you can help control is the drain pan under the cooling coil. Level the unit and locate the drain so that the pan drains completely if possible. Drain other locations where water may accumulate and have leaks repaired quickly before growth takes off. Wet building materials must be quickly dried or removed if growth is to be minimized.

Most organic matter is an excellent source of food for microorganisms. Since organic matter is so common, it is impossible do eliminate all sources of food. For example, building materials, fabrics, and carpet usually contain a high percentage of organic matter. For this reason, it is often necessary to remove these materials when they become wet in order to avoid harmful levels of microbial growth. Much of the soil and dirt that is present in homes, offices, and plants is also organic in nature. Therefore good housekeeping is an important part of a clean indoor air strategy.

Good housekeeping inside of the HVAC system is even more important. Moisture and temperature conditions are normally ideal for rapid microbial growth. If a large amount of soil is present, extensive colonies will form. These growths actually become thick enough on heat exchanger surfaces that they significantly reduce heat transfer efficiency. It is not uncommon for built up growth to reduce efficiency as much as 29%. The bacteria that grow on coils and in drain pans are of a category known as "sulfite fixing bacteria". As part of their growth cycle, they remove sulphur from the air and give off sulphur dioxide which in water, forms sulfuric acid. This acid causes much of the corrosion in air handlers and other system components and dramatically shortens component life. An even more immediate problem is the reduction in air flow resulting from even small accumulation of growth. More energy is needed to force air through the coil and the reduced air flow changes the operating characteristics of the system, resulting in poor efficiency and moisture control.

Most importantly, parts of colonies that are in the HVAC system are constantly being broken off and blown by the air stream into the conditioned space. Thus, contaminated HVAC systems are a major source of the biological contamination that causes do much illness and discomfort in indoor environments. It is vital to keep the interior of the entire system clean and free from growth. When the HVAC system is serviced, the technician must clean accumulated growth from cooling coils because of the obvious negative effect on efficiency. It is equally important to clean the drain pan, blower housing, blower wheel, and other parts of the interior of the air handler. Most system growth originates in the air handler so control must start there.

The need to clean the air ducts is less agreed on. On the plus side, a heavy buildup of contamination in a duct can easily be dislodged by air currents and blown into the conditioned space. That fact argues for cleaning of any duct that is highly contaminated. On the other hand, air ducts are normally very dry. It is unusual for any active microbial growth to take place in air ducts. The organisms that are in ducts have probably been blown there from other locations (most likely the air handler). Because of this, they will probably stay where they are and will not increase in concentration. There are exceptions to this that those in the duct cleaning industry will point out. There are often active growths on turning vanes, dampers, and the supply grills associated with ducts. This growth must be removed and regrowth prevented. Whatever your personal business decision is regarding air ducts, it is important that HVAC systems be clean.

Even where water and organic material are being controlled as well as possible, significant growth will take place inside of HVAC systems. Unless aggressive action is taken, colonies will concentrate to the point where a potentially harmful level of organisms will exist in the conditioned space. BBJ Microbiocide is a product that has been specifically formulated to significantly reduce the number and size of microbial colonies (known as bioburden) in air conditioning and humidifying systems by retarding their growth. This product actually prevents the slime growths that are such a problem in HVAC systems. BBJ MicroBiocide, an EPA and USDA registered product, may be used in federally inspected meat and poultry processing plants in accordance with instructions on the EPA registered label and is listed under the NSF Nonfood Compounds web site as well. Food safety and product quality are essential cornerstones in the food industry. As a broad-spectrum antimicrobial, BBJ MicroBiocide not only kills fungi and bacteria in air-conditioning and refrigeration systems but also inhibits their growth for months at a time depending on your standard sanitizing operating procedures. The proper use of BBJ MicroBiocide as part of your SSOP program will lower the chances of the air-conditioning and refrigeration systems being a source of microbial contamination.

BBJ Microbiocide should be applied in the system following each cleaning of the system. This will retard the growth of hidden colonies and CFUs that were missed in the cleaning that could support rapid regrowth. To be totally effective, use of BBJ Microbiocide must be part of a routine preventative maintenance program. Depending on the level of general facility contamination and the use and occupancy of the facility, BBJ Microbiocide should be applied at intervals of a month to six months. In normal use, enough BBJ Microbiocide should be applied to thoroughly wet the surface applied to. It should be applied to coils until it drips off and applied under pressure so it penetrates the full depth of the coil. If added to standing water, the quantity added should equal the volume of water. A semiannual or quarterly visit that includes servicing filter media, application of BBJ Microbiocide, and a general operational check/adjustment can be a profitable service that provides great value to indoor air health.

Mr. Baker's field of expertise is the control of contamination in air-conditioning and ventilating systems by mold, mildew and bacteria. He writes and speaks frequently about the efficacy, legal risks, and regulatory issues involved in various control strategies. He serves on ASHRAE Technical Committee TC 2.3, TC 2.4, TC 9.8, and Sampling of Airborne Particulate Concentration in Commercial and Residential Buildings GPC 17P. He also serves as a member of ASTM D22.06 (Indoor Air Quality) and is on the Board of Directors of the Indoor Air Quality Association and the Florida Public Health Foundation. Because HVAC applications encompass new uses from an U.S. EPA regulatory standpoint, Mr. Baker works closely with the EPA and industry groups, including serving as the chair of the IAQ committee of the Consumer Specialty Products Association, to help formulate policy in this area.

Bob Baker is Chairman and CEO of BBJ Environmental Solutions, Inc., a company specializing in providing clean air through environmentally responsible products, such as BBJ MicroBiocide , BBJ Micro Coil Clean , "FreshDuct Odor Eliminator ", and BBJ Mold and Mildew Remover™ as well as the revolutionary new Power Coil Clean™. For additional information, Mr. Baker can be reached at (800) 889-2251 or through the company web site at http://www.bbjenviro.com.