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How to prevent Airborne Contamination Issues


Most food and beverage travel a long way from the paddock, orchard or field to plate and this makes contamination control a difficult and immensely important process. While the journey is long, the most crucial part of contamination control is in processing facilities and warehouses. The journey from the source to the first processing facility is quick and generally easy to control. Once the raw product reaches the processing facility though, it is manipulated and exposed, and then it is stored in a warehouse for what can be a very long time.

Paddock_to_plateAirborne contamination is the most difficult form of contamination to protect against. The ingress of contaminated airborne particles puts everything in the warehouse at risk and this means that nothing but a complete seal is adequate. 

Airborne contaminants can be segmented into Aerosols (fine solid or liquid particles in gas) and Bio aerosols (fungi, bacteria and pollen). But a third category of airborne contamination threats should not be ignored; the threat of flying pests (flies, birds etc…). While only sometimes a contamination threat in terms of presence in product they are carriers of disease and contaminants that may stay behind long after the presence of pests has gone.


The major ingress of airborne contaminants within a facility is through doorways. There is also movement through ventilation, gaps in walls and windows but doors present the largest transfer area and as such are the most crucial feature to consider in your airborne contamination prevention efforts. Below are some major things to consider when attempting to use your doors to reduce airborne contamination in your facility.

Open All Hours

It’s a simple equation: the less time doors are open in your facility, the less opportunity there is for contaminants to enter. However, the ways in which you can reduce open time are numerous and choosing the right course of action involves weighing all factors. For example doors with heavy traffic suffer from maintenance issues following frequent usage as well as damage caused by crashes. 


It is important that you choose a door that is resilient and reliable for this purpose but at the same time, is quick enough to reduce open times. A door made of substandard parts will break down more frequently, creating delays and potentially being open permanently until fixed.

Look at the warranty, if they have no long-term guarantees or support, you should be asking; “why not?” Rapid doors are essential in blocking the aerosols that follow in the wake of a forklift when it crosses through the doorway. The ultimate solution is thus a fast, good quality and long lasting door.

Protection on All Four Sides

While the speed and reliability of the mechanical elements of the door are important, it is also crucial to consider the seal of the door. The tighter the seal, the less opportunity there is for ingress of contaminants. Impact is one of the major causes of broken seals and that is why investing in rapid doors with a crash-out or self-repairing feature is really important.

High-speed doors should be fast enough to avoid major collisions but having a crash-out feature, like the Movidor High Speed Doors from Remax Products, allows the door to be knocked out from its guide and while not damaging the seal; the door will then realign automatically. Lower cost Rapid Doors with no crash-out feature will normally require a call out to realign the door back into its tracks and therefore carry regular unforseen additional costs on a monthly basis. You are very likely going to save on maintenance costs in the long run with purchasing a slightly more advanced door containing self-repairing features, and therefore requiring less call out fees throughout the life of the door.

This feature is part of what keeps downtime to a minimum but of equal importance is the way it keeps the seal unimpaired throughout the doors lifespan. It is important to consider other contamination possibilities involved with the door. Another major feature is the ability of the door to shed dirt, dust and contaminants both in its everyday function and during wash down. Roller doors such as the ones described above, should be easily washable and made of an appropriate fabric that is fully extended when the door is closed (preventing any microbial and debris build up around the drums) and all exposed mechanical metal parts should also be constructed using stainless steel to reduce rust / wear and tear. Watch this video of Movidor High Speed Door being washed down with high pressure cleaner. Read about a recent project at Cadbury involving the installation of a Rapid Roller Door in their wash-down bay, click here.

Water, Water Everywhere

Water is a major concern for contamination in any facility but it becomes even more of a concern when you consider how easily it can become aerosolised. Airborne bacteria, yeast and mould can be generated in many ways in a processing facility, whether by heating systems, ventilation and air conditioning systems or even refrigeration systems. ChickenDrains are breeding grounds for these ‘soon-to-be-airborne’ contaminants and as soon as a drain floods, microorganisms on the surface can become aerosolised and dispersed throughout the facility. High pressure spraying (although necessary) is also a culprit of aerosolising microorganisms. This is where the door becomes invaluable because it essentially functions as a drag net that catches all the aerosolised microorganisms and stops them moving into another area of the facility.

However, the door isn't always closed; in an environment where condensation may occur, the door (when rolled up in the open position) can often drip condensation onto products below it. This is most dangerous when food products are being transported in and out of the warehouse, constantly moving beneath open doors. The condensation on the door can become contaminated and mixed in with other dirt/dust/contaminants in the facility or on the outside of the door.

The best solution in this instance, is to fit a pneumatic drip-catch tray that moves under the roll drum when the door is retracted. The drip tray helps to prevent contaminated liquid from dripping onto the product/pedestrians passing below. Another solution is to employ an angled bottom bar that directs water residue to one side. 

Water pooling around the base of the door is a particularly common symptom of inadequately insulated doors that are used for cold storage. A poorly insulated door used for cold storage purposes will essentially function as a condenser, as moist air hits the chilled panel and forms condensation. The greater the heat (or cold) transfer through the door, the more likely this is to be a problem. For example a high traffic area might dictate a high-speed bi-parting freezer door option. Where the right fit would be a high-speed freezer door, sometimes the most ideal option may not be available or considered too expensive in which case a roller shutter door is fitted instead or another poorly insulated door. This decision would result in a lot of heat transfer, thus increased power costs for the extra cooling needed to make up for the heat transfer and the increased possibility of pooling around the door base.


Choosing the right door for the right application is absolutely essential. Consultants who see a variety of environments and know all the door options are at hand to give you advice and conduct a free site assessment. Make use of free advice from the experts before you make a decision. 

If you found this information useful, read our free contamination prevention guide. Which is available for download by clicking the button below.

Free Guide: Contamination Prevention in Food Manufacturing


Topics: cold storage doors, airborne contamination

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