Airborne contaminants at food processing facilities represent a serious threat to the safety of food and people’s health. Particles like dust, bacteria, mold, and yeast can get into food and cause health problems for those who ingest the food. How can proper air filtration and sanitization policies assist in protecting food from airborne contaminants?
What are Common Airborne Contaminants at Food Processing Facilities?
One of the most common airborne contaminants in food processing facilities are bioaerosols. Bioaerosols are airborne contaminants made up of liquid or solid microscopic particles which carry microbes through the air.
“Bioaerosols are frequently created when a source of microbes is disturbed, which launches the particles into the air where they remain suspended for varying lengths of time, depending upon their size and airflow patterns for example,” says Mark Davidson, Camfil USA Food & Beverage Segment Manager. “Bioaerosols could be created by using high-pressure hoses to wash down holding pens, the use of compressed air lines without filters, by poorly installed air handling units, as well as foot or vehicle traffic through stagnant water. Bioaerosols can also originate in neighboring buildings or fields. Whether originating from inside or outside the food processing facility. These bioaerosols can come to rest on food or on contact surfaces where preparation work is performed.” (1)
The most common bioaerosols include microorganisms like Salmonella, E. coli, Listeria, Bacillus, and Clostridium. Yeasts and molds are also common sources of contamination, and they frequently become predominant in food processing facilities when conditions for bacterial growth aren’t optimal, such as on foods with a high amount of salt. Viruses such as norovirus and hepatitis A are also common contaminants.
What Are the Effects of Contamination at Food Processing Facilities?
The effects of contamination in food processing are twofold. Contamination can cause significant product loss during production, reduced shelf life or product returns. These added expenses are a financial burden on the profitability of a facility. Far more important however is the negative effects on public health created by contaminated food. Bacteria and viruses can all cause different foodborne illnesses that can have a variety of different effects on people’s health but are the most dangerous to the very young, the very old, pregnant women, and people with poor immune systems.
“Salmonella, E. coli, and Listeria all cause the diseases associated with exposure to these pathogens. Bacterial-based foodborne illnesses are typically contracted by ingesting the food in question,” says Davidson at Camfil. “Common symptoms of infection from foodborne illnesses include vomiting, abdominal pain, chills, fever, and diarrhea.” (2)
Exposure to Clostridium botulinum can cause the disease botulism which can cause headaches, blurred vision, weakness, paralysis, and dizziness. Botulism can be fatal, so it is extremely important that potential sources of botulism are neutralized immediately.
Viral infections such as norovirus can cause inflammation of the stomach and intestines, and people can pass the virus to one another rather easily.
How to Protect Food from Airborne Contaminants with Air Filtration
A food processing facility with a carefully developed HACCP plan should identify the critical areas where hazards can occur. One method to control the hazard of bioaerosols contamination is with the proper air filtration.
Broadly speaking, there may be up to three types of air filtration systems in a food processing facility. The main HVAC system that brings air into the facility which is typically located on the roof and controls the heating and cooling in the building. Second; filters that protect the air entering into a specific piece of equipment can be thought of as process filters. The HEPA filters protecting aseptic systems are a good example of this. Finally, food processing plants may have stand-alone individual air purification systems that are strategically located near areas known to generate contaminants.
Food processing facilities should be constructed with the placement of the HVAC systems optimized to ensure exposure to bioaerosols remains as low as possible, and the proper filters should be chosen to capture these bioaerosols.
“One of the primary sources of contaminants and bioaerosols is water, and a facility’s own HVAC system could be the culprit. HVAC systems should be designed to ensure that water does not pool in them. Cooling coils, drip trays, and evaporative condensers should be maintained and checked often for the possibility of contaminated water,” explains Davidson, “Optimal airflow management is also important for reducing the spread of bioaerosols, and a good principle to follow is that the more hygienic an area must be, the higher the pressure of that area should be.” (3)
“In those areas identified as potential sources of internally generated contaminants or where additional airflow is required to maintain a higher pressure, stand-alone air purification systems can add that missing layer of protection against airborne contamination.”
Properly designed filtration systems are wasted if the appropriate air filters are not selected. High-efficiency filters should be employed to capture bioaerosols. Be sure to look for filters labeled with both a MERV and MERV-A rating. The – A is a designation, such as MERV 13-A, which means that the filter has been tested in conditions designed to simulate real-world situations, and will not drop in efficiency over time like filters only rated with a single MERV value.
It is the responsibility of each individual facility to determine the specific MERV rating to use, if HEPA filters are needed or if additional stand-alone purifiers are required. Each application and process is different and no one solution is suitable for all.
What Can You Do to Protect Food from Airborne Contaminants?
Protecting food from airborne contaminants is a matter of public health and the responsibility of those who work at food processing plants. Those responsible for air quality at food processing facilities should be sure to consult with qualified professionals who can help you determine possible sources of dangerous bacteria and bioaerosols both inside and outside of the plant. Plant managers should also contract with licensed professionals to ensure that proper installation and regular maintenance of air filtration systems is performed.