Compressed air requirements in the Safe Quality Food (SQF) Edition 9 Code – Food Manufacturing reference the use of inert gasses or air that contacts food or food surfaces such as packaging or equipment surfaces. In the food and beverage industry, inert gases are used for sparging (ex: nitrogen in wine or in nitro coffee) and carbonation (ex: carbon dioxide in soft drinks). Air is used in drying operations. Compressed air is useful when cleaning food containers, conveyors, and other machine parts. Modified Atmosphere Packaging (MAP) is another application where a food-grade mixture of gas is injected into a package to extend shelf life and maintain the gustatory quality of food.
The purity of compressed air is especially critical in Ready-to-Eat food applications where exposed finished products (ex: Produce packed in MAP) may become contaminated prior to packaging. The control of air quality and inert gas purity is addressed in your Good Manufacturing Program manual (GMP), also referred to as Pre-requisite programs (PRPs). Look up sections on Premise control, Equipment, and Utility Maintenance and Repair.
SQF 9 Requirements are not very prescriptive regarding the use of compressed air. They state the following:
Compressed air requirements in SQF 9 Food Manufacturing – See Section 11.5.5 Air and Other Gases
11.5.5.1 Compressed air or other gases (e.g., nitrogen or carbon dioxide) that contact food or food contact surfaces shall be clean and present no risk to food safety.
11.5.5.2 Compressed air systems and systems used to store or dispense other gases that come into contact with food or food contact surfaces shall be maintained and regularly monitored for quality and applicable food safety hazards. The frequency of analysis shall be risk-based and at a minimum annually.
The SQF Code 9 Glossary (p 87) provides a bit more guidance:
Compressed Air Monitoring: A program that includes particles, water, oil, microbiological, and relevant gaseous testing in compressed air or other gases. Verification of the effectiveness of compressor maintenance and filtration that a management facility has in place.
So does an earlier guidance document published in October 2019 for SQF 8.1 Food Manufacturing (See module 11, page 48)
[Requirement] does not apply to air that does not come into contact with food or food contact surfaces. Purity means the absence of contaminants that could cause a food safety hazard.
Contaminants in compressed air include particulates, including dirt (microorganisms, atmospheric dirt and solid particulates, rust, and pipe scales), water (water vapor, condensed liquid water, and water aerosols), and oil (oil vapor, liquid oil, and oil aerosols). Air compressor(s) must use food-grade oil.
Preventive maintenance programs need to ensure that an appropriate filtration program is in place at the point of use and the filters are cleaned or changed at a frequency appropriate to the product and process or following any maintenance to air supply source or equipment. Any maintenance must be done in a hygienic manner.
What do I need to do to be GMP and SQF compliant?
The first step in fulfilling the intent of the SQF code is to purchase food-grade gases from approved suppliers. SQF practitioners or purchasers generally request a Certificate of Analysis (COA) or Letter of Guarantee (LOG) for such purchases. COAs and LOGs must be kept on file and may be requested by SQF auditors.
Secondly, a risk assessment of the food manufacturing process must be performed to identify chemical, biological, and possibly physical risks associated with the use of air compressors, dryers, and gas/air dispensing systems. This is best accomplished by the PCQI/HACCP team developing and maintaining your food safety plan(s). As the SQF 8.1 guidance suggests, air compressors must utilise food-grade lubricants or be of the oil-free type.
Thirdly, your Preventive Maintenance (PM) Program (see Module 11 of the SQF Code Edition 9) will include the monitoring and maintenance of compressed air, MAP systems, and drying equipment. These activities require regular inspections to ensure proper air filtration at the point of use. Filters must be cleaned and replaced at regular intervals and must prevent contamination of food and package. Contaminants may include harmful bacteria, toxic chemicals, and other contaminants. SQFI (8.1 Code guidance for Module 11) suggests controlling pathogenic microorganisms at point-of-use using sterile filters (0.01-micron minimum, efficiency of 99.999% achieving 5-log reduction). An effective PM program should be in place to maintain the integrity of the filter(s).” Verification of specifications from the filter manufacturer is an appropriate validation. An earlier SQF FAQ document (2017) on compressed air mentions a “recommended filter size at the point of use is 0.1 micron, or as determined as appropriate by a risk analysis).”
The mention of the risk assessment is important here as it relates to the food safety risk level associated with the food and process. 0.1-micron filters may be suitable in low-risk environments such as bakery producing baked goods with no cream fillings or icing. When inspecting compressed air lines, nozzles and air hoses must be in good repair, clean, and sanitized. They must be kept off the floor when not in use. Air testing should be conducted based on risk, a minimum of annually. Testing may be done in-house or may be contracted out to an approved service provider. Testing may include aerobic plate count and/or indicator microorganisms (ex: Enterobacteriaceae, Coliforms) as appropriate to the site. Depending on the type of process, compressed air may be tested for moisture since humidity could have detrimental effects in dry food operations. More information here.
Regulatory guidance
FDA Listeria Monocytogenes guidance (2017) suggests that “depending on your product, your process, and the design and construction of your plant, it may be appropriate to use High-Efficiency Particulate Air (HEPA) filters that have an efficiency of 99.97-99.99% at 0.3 micron for removing bacteria, yeasts, and molds. Regular micro testing of compressed air at the point of use can be performed annually or more frequently to rule out excessive microbial contamination including with Yeast and Mold.” FDA’s 2008 Guide to Minimize Microbial Food Safety Hazards of Fresh-cut Fruits and Vegetables suggests filtering “compressed air (such as oxygen (O2), nitrogen (N2), and carbon dioxide (CO2) used in modified atmospheric packaging) when such air contacts fresh produce using a 0.3-micron filter (with an efficiency of approximately 75%).”
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