Passing your compressed air analysis: Tips and troubleshooting
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Howdy IFSQN Webinar Viewers,
Here are answers to the top 10 questions we received.
Please contact us if you have any further questions. We're here to help: 1.800.AIR.1024 ext. 5 - Trace Analytics
Q1. Where can I find limits for compressed air contaminants?
A1. ISO 8573-1 has a variety of purity limits for particles, water, and oil. See BCAS Food and Beverage Grade Compressed Air Best Practice Guideline 102. They state a class [2:2:1] for direct contact and [2:4:2] for indirect contact. SQF states you should perform a hazard analysis to determine limits for the safety of your specific product(s). See our risk assessment webinar here.
Q2. What is the best method/device for sampling compressed air for microbes?
A2. ISO 8573-7:2003 states under Annex B "normative" quantitative sampling methods that, a slit sampler (impaction air tester) shall be used for detection of microorganisms. CAMTU, while a great way to qualitatively analyze your compressed air, is not validated by the original equipment manufacture (OEM) to measure colony forming units quantitatively. Therefore, CFU/m3 should not be extrapolated from the CAMTU results because the OEM does not validate it for such, as the manual is written. The SAS Pinocchio Super II is an excellent validated piece of equipment that works for this process and adheres to ISO 8573-7.
Q3. What are the sampling times for microbial tests?
A3. Microbial sampling times for compressed air impact samplers are based on the validation times and flowrates that the OEM provides in the equipments manual, or the validated procedures they provide. Often times the equipment used is accompanied with a IQ/OQ/PQ certificate. Since the media being used typically is a broad spectrum agarose (Tryptic Soy Agar), there is no difference between sampling times for yeast/mold, as they will all generally grow once impacted on the agarose surface.
Q4. Is the CAMTU microbial test unit by Parker Balston appropriate for compressed air monitoring?
A4. CAMTU, while a great way to qualitatively analyze your compressed air, is not validated by the original equipment manufacture (OEM) to measure colony forming units quantitatively (see page 3 of CAMTU manual). Therefore, CFU/m3 should not be extrapolated from the CAMTU results because the OEM does not validate it for such, as the manual is written. The SAS Pinocchio Super II is an excellent validated piece of equipment that works for this process and adheres to ISO 8573-7.
Q5. Are hydrated plates an acceptable way to sample compressed air for microorganisms?
A5. If your monitoring plan does not require your procedures to adhere to ISO 8573-7:2003 you are welcome to use the 3M hydrated plates procedure. However, ISO 8573-7:2003 states under Annex B "normative" quantitative sampling methods that, a slit sampler (impaction air tester) shall be used for detection of microorganisms. The bag method is a more passive air sampling method, where air is bouncing off the walls of the sterile bag in hopes of hitting the plate. An impact sampler forces air in a single direction, dimpling the agarose for a more active measurement, that adheres to ISO 8573-7.
Q6. Is it necessary to use food-grade oil in your compressed air system?
A6. It is recommended by SQF. Refer to the BCAS Food and Beverage Grade Compressed Air Best Practice Guideline 102. It is an excellent reference and discusses food grade oil usage.
Q7. What are the potential microbiological pathogens in compressed air?
A7. Many organisms can be isolated from compressed air: slime molds, filamentous fungi, most are facultative anaerobes (microbes that can live in oxygen poor and oxygen rich environments). There are ways of helping to eliminate the possibility of colony forming units in your compressed air/gas, and that is through your monitoring plan and preventative maintenance. Multiple factors can influence the type(s) of microbial contamination found in your compressed air/gas system, so limiting the list to just a few genera and species isn't ideal. Additionally, compressed air/gas systems often have moisture traps to help eliminate the humid environment these microbes thrive in, it should be noted that the related dessicates should be monitored routinely. Facultative anaerobes like E. coli, S. aureus and B. subtilis are capable of causing disease in humans and are often found in the environment and the human microbiota.
Q8. What is the best material for piping our compressed air lines?
A8. What materials you choose depends on your application and product, as well as your HACCP/Risk Assessment. Minimally, we would suggest aluminum as a material for your piping. It is light, durable, and resists corrosion. However, for more critical applications, stainless steel may be more appropriate. More important that your piping is your point of use filtration. Ensure that your point of use filtration is appropriate to your needs, of high quality, and well maintained.
Q9. How often should compressed air quality be tested?
A9. A quarterly or semi-annual test schedule is great for the first year or two. Once you have sufficient data points and information on how your system is performing, you can adjust to assure compressed air is contaminant free throughout the year.
Q10. Are there any limits for microbes in compressed air?
A10. None that we have found in the food industry. The pharmaceutical industry tends to use cleanroom classifications and limits.
The Compressed Air Testing Experts,
Trace Analytics
1.800.247.1024 ext.5