環境空気試験：何を、どのように、誰が、いつ、どこで？

Environmental air quality plays a critical role in food safety, product integrity, and regulatory compliance. This SQF digital seminar, presented by Damian Alexander from the SQF Institute and Jonathon Sauseda from TRI Air Testing, Inc., provides practical, risk-based guidance on environmental air testing within food manufacturing and processing environments, with a specific focus on compressed air and ambient air systems. 

Why Environmental Air Testing Matters 

Air should be considered a potential food contact surface in food manufacturing operations. Poor air quality can introduce microbial, physical, and chemical hazards that negatively impact product safety, shelf life, and audit performance. This seminar explains how air contamination can occur and why proactive testing is essential for maintaining effective preventive controls under SQF programs. 

Understanding Compressed Air and Ambient Air 

Ambient air is drawn into compressors and condensed under pressure, meaning any contamination present in the surrounding environment can be amplified within compressed air lines and distributed throughout the production system. Common food industry applications for compressed air, including packaging operations, surface and equipment cleaning, capping and sealing, product conveying, and process instrumentation, often involve direct or indirect contact with food or food contact surfaces, making air quality a critical food safety consideration rather than a simple utility concern. 

Compressed Air System Design and Maintenance 

Attendees are guided through how compressed air systems are created and maintained, including compressor types, heat generation, condensation, and particulate buildup that naturally occur during air compression. The discussion highlights how moisture accumulation and temperature fluctuations can accelerate system degradation if not properly controlled. The importance of understanding piping materials, filtration stages, micron ratings, and filter change intervals is emphasized, as inadequate maintenance or mismatched filtration can lead to corrosion, microbial growth, oil carryover, and particulate contamination. Over time, these issues can result in inconsistent air quality at the point of use, increased product risk, and greater variability across production lines. 

Who Should Test and How Often 

The seminar reviews SQF guidance on compressed air and ambient air testing frequency, emphasizing that annual testing represents a minimum expectation rather than a best practice. Facilities are encouraged to conduct baseline validation to understand their specific system performance and establish defensible, site-specific specifications. Testing frequency should be risk-based and aligned with factors such as system design, maintenance history, product exposure points, and process criticality, with historical results and trend analysis used to justify increases or reductions in testing over time. This approach supports consistent control, data-driven decision-making, and stronger audit readiness. 

Where to Test for Accurate Results 

Testing should occur at the point of use, where compressed air directly contacts product or food contact surfaces. Additional upstream and downstream sampling locations are recommended to evaluate filtration effectiveness and system consistency, particularly at the furthest points from the compressor. 

Applying ISO 8573 Standards 

ISO 8573 provides internationally recognized guidance for determining acceptable limits for particulate matter, water, and oil in compressed air systems, offering a common framework for evaluating air quality across food manufacturing environments. The seminar explains how different ISO classes define both measurement methods—such as particle counting versus gravimetric analysis—and concentration thresholds for each contaminant type. This structure allows facilities to select specifications that align with product risk, processing conditions, and points of air contact, rather than relying on generic limits. By applying ISO 8573 appropriately, sites can establish clear, defensible air quality criteria that support validation, ongoing monitoring, and audit consistency. 

Mold, Yeast, and Bacteria Testing Requirements 

The presenters also address ISO 8573-7 requirements for microbial testing, including mold, yeast, and bacteria, and explain how microbial contamination can be introduced and sustained within compressed air systems. Both active (instrument-based) and passive (settling plate) monitoring methods are discussed, along with their appropriate applications and limitations. A strong emphasis is placed on using in-line testing equipment at the point of use to ensure samples accurately represent compressed air quality and to avoid false positives caused by ambient air interference. This distinction is critical for generating reliable data, supporting corrective actions, and defending results during audits. 

Establishing Specifications and Reviewing Reports 

SQF does not prescribe fixed air quality limits. Instead, facilities must establish their own specifications based on risk assessment and baseline testing. Effective laboratory reports should clearly identify analytes, results, specification limits, and pass/fail outcomes to support trending, corrective actions, and audit readiness.