The development and evolution of Food Safety Plans for each individual food production facility has included the implementation and upgrading of environmental monitoring programs (EMP). A key part of this is understanding the role of the HVAC system in food industry settings, where it significantly impacts air quality and microbial control.
The goal of an EMP is to gauge and monitor the presence of microorganisms within the manufacturing site. This includes the testing of food contact and non-food contact surfaces with particular focus on high-traffic areas, niche harborage sites, worn structural sites, and wet areas where condensation may have occurred. The sampling for a standard EMP predominantly focuses on surfaces (e.g. belts, floors, drains, floor-wall junctures, doors, posts, bins, pallets, etc.). In addition to testing surfaces in a standard EMP, it is pivotal to consider the role of air quality.
Environmental Monitoring and the Hidden Risks of Airborne Contaminants
The management of air quality can mitigate the incidental introduction of yeast, mold, and bacteria in the production stream or in finished product, post-processing but pre-packaging. Standard sanitation procedures are designed with the treatment of processing equipment and the physical area within the production area in mind. However, if there were a contamination event within an air handling system, re-introduction and contamination of the production area would occur while the air handling system is running.
As such, insight into the quality of air and managing the direction of air flow is pivotal for Food Safety and Food Quality Plans at any manufacturing site. This is important insight to have as it can allow for the prevention of product contamination as well as allow for the troubleshooting and halting of any on-going contamination events associated with poor air quality due to microbial presence, first indicated by spoiled packages.
A well-maintained HVAC system in food industry environments acts as a frontline defense, helping maintain controlled airflow and minimize the spread of airborne microorganisms.
Learn more in our Sanitary Design Course.
Air Sampling Methods: Settle Plates and Device-Aided
When considering air quality at a production facility, one of the first steps to take is to assess what the quality is. This can be performed several different ways, dependent on available resources. The two most popular and easiest to perform are…
- Traditional methods (settle plates)
- Device-Aided Traditional Methods (AES active air sampling, CAMTU compressed-air testing)
Traditional settle plates rely on capturing airborne microorganisms that naturally fall out of the environment. They are inexpensive and simple to use, but don’t provide quantitative data. For that reason, they’re suited for offering a practical snapshot of air quality.
Device-aided traditional methods pull a defined volume of air across an agar plate or hydrated sponge, depending on the unit, which provides quantitative data. They provide precise data for high-risk or compressed-air applications. While more costly and technical, they are part of a robust air-sampling program for your environmental monitoring program when used in tandem with settle plates.
This article provides details about these different air sampling in food manufacturing methods, including when to use each.
The Critical Role of HVAC Systems in Food Industry Settings
In addition to measuring and observing the presence of microorganisms, additional steps can and should be taken to further minimize the potential for product contamination. This includes, but is not limited to, two approaches.
The first approach is the use and upkeep of a proper HVAC system in the food industry, including air filtration and environmental control across the plant. The HVAC system allows for the management of temperature and humidity within the production facility, as well as air flow direction and pressurization.
Managing Temperature, Humidity, and Airflow to Reduce Microbial Growth
By controlling temperature and humidity, microbial growth is mitigated – especially when temperature is kept lower than that considered ideal for most microorganisms. Controlling humidity provides moisture control. Managing humidity and air moisture helps avoid reaching the dew point, the temperature at which moisture condenses from a gaseous to a liquid state and onto a surface.
Lower moisture availability reduces microbial viability and growth. Moreover, high air moisture levels can also skew measurement techniques by altering particle density and collection reliability.
Pressure Differentials and Contamination Control
The second approach to managing further contamination is the use of air pressure gradients. These gradients help prevent cross-contamination between the raw ingredient area, production zone, packaging, and warehouse.
A pressure gradient is established because air naturally flows from higher pressure areas into lower pressure ones. In food production facilities, this means creating positive air pressure in clean areas such as packaging rooms, so air only flows outward from these spaces.
This air gradient strategy depends entirely on a well-functioning HVAC system in food industry environments, which must maintain proper room-to-room pressure zones.
Avoiding the Risks of Negative Air Pressure in Older Facilities
While keeping the positive air pressure strategy in mind, it is equally important to monitor for negative pressure zones – particularly in older buildings. These are often caused by excessive exhaust fans or poor unit placement. Negative air pressure allows unfiltered air from outside the facility to enter, introducing water, dust, microbes, and other contaminants.
Any time unfiltered air is introduced into the production area without prior filtration, the risk of contamination significantly increases.
Routine HVAC Maintenance for Food Facilities
To maintain consistent air quality and minimize contamination risks, routine HVAC maintenance is essential. Filters should be changed regularly, ducts should be inspected for microbial buildup, and pressure systems recalibrated based on room function and traffic levels.
Monitoring differential pressure, airflow rates, and humidity levels on a scheduled basis helps ensure the HVAC system continues to support food safety initiatives. Investing in a robust HVAC maintenance plan also reduces the likelihood of sudden failures or contamination events caused by unnoticed system degradation.
Final Thoughts: Air Quality as a Key Food Safety Strategy
Overall, it is important to understand the state of air flow and quality within each production facility. In measuring at predetermined frequencies, QA/QC staff can maintain a pulse on the presence of yeast, mold, and bacteria that are airborne and translocating throughout the facility.
Furthermore, by understanding the management and flow of the air, preventive measures can be put in place (i.e. air flow gradients) to minimize product contamination. By minimizing contamination, the goal of providing a safe and high-quality product to the consumer is attained without the presence of harmful microorganisms or spoilage organisms.
Ultimately, a reliable HVAC system in food industry facilities is not just a comfort measure – it’s a crucial safeguard for public health and product integrity.
Contact our Customer Service Team if you need air sampling for your food facility. We offer settle plates, rental device-aided traditional air samplers, and microbiology testing to support your food safety program.
