Shutting the Door on Pathogens

Protection All the Way Around. A tight seal on all four sides of the door panel is as crucial as the seal on product packaging. The optimal roll-up door barrier consists of full-height seals enclosed by the side guides and brush or vinyl seals along the header and bottom bar. If seals prevent air infiltration and energy loss, pathogens can be stopped at the door.

This seal is compromised when the door is hit by a forklift. The doorway could be unprotected for hours until the repair crew arrives or for days if there is panel damage. Repairs can disrupt the flow of ingredients and products to the production and shipping areas, especially if there are few doors into the room.

For a high-speed door, the rapid opening should make these occasions rare. But when collisions do happen, the door panel should have the capability to break away from its guide to prevent damage. The ability to quickly reset the door into the guides minimizes room exposure.

In this high-speed setting, high performance puts high demands on the door. Effective counterweight design eliminates stress and overworking of the door motor.

Clean Getaway. The door must be as easily cleaned and sanitized as all other processing equipment and containers used in the process. Like the equipment, the doors must be made of nontoxic materials, particularly if the doorway leads into areas designated as clean rooms.

These kinds of doors must meet the requirements for current Good Manufacturing Practices (cGMP) as defined under the Food, Drug, and Cosmetic Act, which dictates that equipment and utensils in food production areas must be chosen and designed to prevent disease and adulteration. Metal parts should be constructed of stainless steel, including the frame and the roll-up drum. Some models have removable frames for easy cleaning.

For roll-up style doors, nonporous USDA/FDA approved curtain fabric enables doors to easily shed dirt and debris during wash down. Door curtains should be completely extended when doors are closed, preventing microorganisms and debris from collecting around the drums.

Chasing Moisture Away. Major sources of contamination in food processing facilities are wastewater, rinse water, and spilled product that become aerosolized. Airborne bacteria, yeast, and mold are generated in processing facilities by heating, ventilation, and air conditioning systems. These systems contribute airborne microorganisms under normal operation because they provide fertile areas for growth due to moisture.

Sink and floor drains can harbor microorganisms because they are humid and contain nutrients from wastewater that provide a fertile growth environment. Flooded drains cause microorganisms on the surface to become aerosolized and air disperses them, causing increased levels of aerosolized bacteria in the food processing facility. High pressure spraying also causes an increased level of aerosolized bacteria.

Here’s where the door itself, especially a roll-up door, can sometimes become part of the solution yet part of the problem. The curtain plays an excellent role as a large catcher’s mitt for aerosolized microorganisms, blocking the entry of these invaders into the next step in the process. But these pathogens are rolled up with the door curtain as it opens. As product passes underneath the opening door, the bioaerosol can drip on the food below.

A roll-up door can be outfitted with a pneumatic drip-catch tray that moves under the roll drum when the door opens to prevent adulteration and contamination. When the tray is in place, contaminated liquid is stopped from raining on the food.

After traffic passes through the doorway, the tray moves out of the threshold and back to the original position, allowing the door to close. These trays do not interfere with efficient door operation, and they are the first line of defense in enabling compliance with cGMP, HACCP, USDA, and other regulations.