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Explore this issueApril/May 2013
Most of our food travels a long way from the farm to the dinner plate. The most crucial yet controllable part of that route is within the four walls of the food processing plant. After raw food hits the delivery dock at the processing facility, it can travel hundreds of feet through various rooms as it is transformed into packaged product. Food can be exposed to any number of contaminants at critical control points.
Pathogen Air Raid
Airborne microorganisms represent a serious threat to quality and safety as product moves from one part of the processing plant to another. According to a study commissioned by the American Society of Heating, Refrigerating, and Air Conditioning Engineers and conducted by Dr. A. J. Heber of Purdue University’s Department of Agriculture and Biological Engineering, these bioaerosol emissions may be carried throughout a processing plant via airflow through doorways and other openings. Dealing with these doorways can reduce the flow of contaminated air and mean additional benefits for the food operation as well.
An aerosol is the suspension of fine solid or liquid particles in gas. Bioaerosols are airborne contaminants that include bacteria, fungi, viruses, and pollen. These free-floating microorganisms may be present in the air as solids (dust) or as liquids (condensation and water) and they are an important bacterial vehicle.
In their paper “Controlling Airborne Microbial Contamination,” Chris Kerth and Crystal Braden from Auburn University state that “with air being considered a potential source of product contamination, the avenues which can allow the air inside the facility to become contamination must be controlled.”
It’s said simple practices such as keeping doors closed is essential in controlling air contamination. That’s easier said than done. Doors with heavy traffic suffer from maintenance issues that arise from frequent usage and damage caused by crashes. Deficiencies in door design can mean that even when the door is closed, contaminants still find a way through. As a result, proper door selection becomes important in preventing contamination.
Doors—Passage and Protection
Walls and doors are used to separate clean and unclean areas, but improperly sealed doorways can defeat the protection these barriers provide. The door industry has engineered doorway solutions that minimize bioaerosol travel and transport as product moves through the process. These doors not only meet the demand for increased productivity and reduced maintenance costs, but also satisfy compliance standards set forth by Hazardous Analysis and Critical Control Points (HACCP) and other food safety programs.
In order to contribute to bioaerosol flow suppression, doors should offer the following measures of protection.
Leaving Microbials Behind in the Rush. According to Dr. Heber, “the speed at which a door operates definitely could affect dispersion or movement of bioaerosol emissions to clean rooms in a food processing operation.“
Slow operating doors compromise quality and safety by enabling dust and fumes to travel with the forklift between areas. Slow speed can also reduce control over desired temperatures, threatening food quality. The faster a door operates, the more effective it serves as a barrier.
Rapid door operation means that food is not only moved faster along the process, but it is moved safer. Seconds count when it comes to outracing bioaerosols while maximizing efficient product handling. For an 8-foot high door that opens at speeds up to 100 inches per second, the doorway will be open for as little as 5 seconds as the forklift hurries through.
High-speed doors and minimal opening time mean doorways are closed as much as possible, maintaining air balance.