SQF Air Purity
Although compressed air purity testing is not new to the food industry, this is the first certification group that made it a requirement in the United States. Compressed air contamination can occur in numerous ways, and if undetected can contaminate your final product. SQF auditors are asking for test results that address particles, water, oil, and microbial levels for the new SQF air purity requirement. Common breathing air specifications do not fully address the needs for compressed air purity used in manufacturing. Breathing air specifications do not address particles by size, microbial contaminants, and typically allow a much higher level of hydrocarbons (oil aerosol and vapor) than is considered safe for food production. Breathing air specifications focus on gases such as oxygen, carbon monoxide, and carbon dioxide that are not problematic for food processing. ISO 8573 is a compressed air specification often used in the food industry that addresses the testing for particles, water, oil and microbial contaminants in compressed air.
SQF has not established acceptable limits for air purity. The following purity limits are from the BCAS (British Compressed Air Society) Food and Beverage Grade Compressed Air Best Practice Guideline 102, revised in 2013.
SQF Air Purity Compressed Air & Gas Testing Specifications
Trace Analytics, LLC is an A2LA Accredited Laboratory in compliance with ISO 17025 as required by SQF. We can test to a wide variety of specifications. Some example specs commonly used in SQF Air Purity are shown below:
BCAS Food and Beverage Grade Compressed Air
|By Particle Size|
(maximum number of particles per m3)
|Vapor Pressure Dewpoint||Aerosol & Vapor|
|0.1 µm < d ≤ 0.5 µm||0.5 µm < d ≤ 1.0 µm||1.0 µm < d ≤ 5.0 µm||°C||°F||mg/m3|
|400,000||6,000||100||≤ -40||≤ -40||≤ 0.01|
|400,000||6,000||100||≤ +3||≤ +37||≤ 0.1|
|Microbial Contaminants||Hazard analysis shall establish the risk of contamination by microbiological contaminants from compressed air. The level of control identified as being required over microbiological contaminants in the compressed air shall be detected using the test method specified in ISO 8573-7.|
|Footnotes||(P) Particle classes 1-5 may not be employed if particles >5 micron are present according to ISO 8573-1.|
Direct and Indirect Contact
Food Manufacturers should identify compressed air used directly and/or indirectly on or in the product. Some Direct Contact examples include compressed air that is used to mix, cut, move, sort or clean your product. Some Indirect Contact examples include cleaning surfaces the product touches, opening packaging the product goes into, belts that move the product, and pneumatic exhaust that may come into contact with the product.
The last thing any manufacturer wants to do is issue a recall. Compressed air, if properly filtered, maintained, and monitored is a safe utility that is used in numerous manufacturing processes. However, when compressed air purity or compressed air quality is overlooked, it can be a contaminant to your product. Common sources of contamination not only include the compressor, but the intake air, piping, and storage. Ultimately, contamination can come from any number of places.
A Checklist for SQF Compliance
Food manufacturers who have never tested the compressed air purity in their manufacturing facility should
- Identify all critical control points utilizing compressed air with direct and/or indirect product contact.
- Perform sufficient compressed air purity tests to determine air quality throughout the production facility.
- Evaluate compressed air purity test results.
- Identify the type of filtration installed on the compressed air system and determine if it is sufficient.
- If compressed air does not meet food quality safety standards, consult with your compressor or filtration professionals to determine a plan of action, which may include additional in-line filtration, point-of-use filters, cleaning or replacing of contaminated piping or storage receivers, improved maintenance, personnel training, etc.
- Perform additional air testing to confirm that the problem has been solved.
- Continue to monitor compressed air purity on a quarterly, semi-annual, or annual basis.
The SQF certification process is designed to help food manufacturers provide safe practices and procedures to prevent contamination in the food chain. Your Quality Assurance Team has the ultimate responsibility in establishing a quality assurance plan that includes compressed air used in the production process shall be clean and present no risk to food safety.
We are happy to discuss your organization’s needs, industry standards, ISO 8573, and more with you to find a program that works for you. For more information on testing for the latest SQF air purity requirements, Contact Trace Analytics today.
SQF – FAQs: What do I need to know?
The information in quotes can be found in the SQF Code, available from the Safe Quality Food Institute Website.
- “Food processing facilities need to operate from a fundamental assumption that compressed air can be a source of chemical and microbiological contamination.”
- “The site must verify and validate that the compressed air used in the facility is appropriate for use and not a source of contamination.”
- “Where external laboratories are utilized to conduct input or product analysis, the laboratories shall be accredited to ISO 17025 or an equivalent national standard.”
Q & A
What is the definition of “Air Purity”?
- “Purity is defined in the SQF Code (Appendix 2: Glossary) and means the absence of contaminants that could cause a food safety hazard. Pure air means the air is free of risk of cross-contamination to the products. Essentially, the air must not contribute any contamination to the product.”
- Use the AirCheck✓ Kit™ K8573NB to test for particles, water and oil contamination and the KPSII Microbial Impaction Sampler to test for microbiological contaminants including colony forming units (CFUs) as low as zero, and yeast, mold, and bacteria identification for any CFUs found.
Do I need to use food-grade oil?
- “Where compressed air comes in contact with exposed product, direct product contact surfaces and interior surface packaging, the air compressor should use food grade oil.”
- If needed, where available, Trace Analytics will be happy to refer you to an AirCheck✓ Service Distributor™ in your area for all your compressor needs.
How do I test the compressed air?
- “Testing can be done in-house or by a contracted party. Test requirements and number of samples will be based on the risk to the product and process. Microbiological testing can include testing for aerobic plate count and/or indicator organisms as appropriate to the operation. Testing for moisture should be considered if moisture is a potential risk to the product (e.g., dry operations). Aseptic sample collection should be used. There are a wide variety of measures available including the use of air sampling equipment, use of sterile sponges, membrane filtration, and others.”
- Trace has the AirCheck✓ Kit™ K8573NB that your personnel can use to sample for the major contaminants in compressed air: particles, water, and oil. We also rent the KPSII Microbial Impaction Sampler for obtaining microbial samples. Trace also has a growing network of trained AirCheck✓ Service Distributors™ available to take samples for you.
How often should I test?
- “Testing is to be conducted to validate the air-filtration control system for the compressed air is effective based on the risk to the product, but at a minimum of once a year. “
- There are many factors to consider when determining your testing frequency. Talk to one of our Team of Experts for more information.
I have a maintenance program and filtration, isn’t that enough?
- “Preventive maintenance programs need to ensure that an appropriate filtration program is in place at the point of use and the filters are cleaned/changed at a frequency appropriate to the product and process or following any maintenance to air supply source or equipment. Maintenance must be done in a hygienic manner. Air should be filtered at the point of use for most operations (recommended filter size at point of use is 0.1µ, or as determined as appropriate by a risk analysis). Nozzles and air hoses are to be in good condition, properly repaired, and maintained in a hygienic state (e.g., cleaned and sanitized). Hoses and nozzles are to be kept off the ground.”
- An excellent air monitoring plan, to address your filtration and maintenance program’s effectiveness, includes taking a sample immediately prior to and after changing your filters. This method provides you with air quality data to review and perform a trend analysis. This sampling plan gives you real data to determine if you are maintaining a safe compressed air supply. Sampling points should be after point-of-use filters and/or as close to where compressed air contacts the product.
What is the equivalent of ISO 17025?
- “ISO 17025 is the international standard for laboratory accreditation. It is a GFSI requirement that external analysis of inputs is performed by laboratories that are accredited to this international standard. However, some countries do not recognize ISO 17025, and have national laboratory accreditation standards in place. Equivalence therefore applies to national standards that are used in-country, instead of ISO 17025.”
- Trace Analytics is accredited to ISO 17025 by the American Association for Laboratory Accreditation.
What exactly does the SQF Code say?
- “3.5.6 Air Quality
- 188.8.131.52 Compressed air that comes into contact with animal feed shall be clean and present no risk to feed safety.
- 184.108.40.206 Compressed air that comes into contact with animal feed shall be regularly monitored for purity.”
- “4.5.6 Air Quality
- 220.127.116.11 Compressed air used in the manufacturing process shall be clean and present no risk to pet food safety;
- 18.104.22.168 Compressed air used in the manufacturing process shall be regularly monitored for purity.”
- “9.5.7 Air Quality
- 22.214.171.124 Compressed air used in the production process shall be clean and present no risk to food safety;
- 126.96.36.199 Compressed air used in the production process shall be regularly monitored for purity.”
- “10.5.7 Air Quality
- 10.5.7.1 Compressed air used in the production process shall be clean and present no risk to food safety.
- 10.5.7.2 Compressed air used in the production process shall be regularly monitored for purity.”
- “11.5.7 Air Quality
- 188.8.131.52 Compressed air used in the manufacturing process shall be clean and present no risk to food safety;
- 184.108.40.206 Compressed air used in the manufacturing process shall be regularly monitored for purity.”
- “12.5.6 Air Quality
- 220.127.116.11 Air, including compressed air used in the distribution facility shall be clean and present no risk to product safety.
- 18.104.22.168 Air used in the facility shall be regularly monitored for environmental contaminants.”
- “13.5.4 Air Quality
- 22.214.171.124 Compressed air that contacts packaging products shall be clean and present no risk to food safety.
- 126.96.36.199 Compressed air used in the manufacturing process shall be regularly monitored for purity.”
- “3.5.6 Air Quality
Trace Analytics can set you up on a regular testing program per your frequency and testing requirements.