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 food-borne 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 environmental condition that can be difficult to 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.

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.

System Hyigene

Good housekeeping inside of the HVAC system is important. Moisture and temperature conditions are normally ideal for rapid microbial growth. If 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 accumulations 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 important, 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.

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. You need to use 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. That actually prevents the slime growths that are such a problem in HVAC systems. Food safety and product quality are essential cornerstones in the food industry. The proper use of a broad-spectrum antimicrobial as part of your SSOP program will lower the chances of the air-conditioning and refrigeration systems being a source of microbial contamination. A semiannual or quarterly visit that includes servicing filter media, application of a broad-spectrum antimicrobial, 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.