Quality grade standards for compressed air in direct contact with food or food-contact surfaces

Core standard basis: ISO 8573-1

ISO ISO 8573‑1 is the internationally recognized standard for classifying compressed air quality, specifying maximum permissible concentration limits for three categories of contaminants: solid particles, water, and oil. For compressed air that comes into direct contact with food or food-contact surfaces, it is generally required to meet Class 0 (Level Zero) or Class 1 (Highest cleanliness grade) requirements, particularly with regard to the oil content, which must reach an undetectable level (≤0.01 mg/). m³）。

GMP and HACCP Requirements for Compressed Air

Good Manufacturing Practice (GMP) explicitly requires that all gases in contact with food be validated to ensure they are oil-free, sterile, odorless, and free from harmful microorganisms and particulate contamination. The HACCP system designates compressed air as a critical control point (CCP), mandating the establishment of monitoring procedures, the setting of action limits, and the implementation of verification and record-keeping for traceability.

Key control parameters for clean compressed air

• Oil content: Oil-free air compressors or certified oil-removal filtration systems shall be used to prevent contamination by mineral oils or synthetic oils;
• Moisture: Dew point temperature is recommended to be ≤ -40℃ (Pressure dew point), to prevent the growth of microorganisms in condensate;
• Solid particles: ≥ 0.1 μm The particle count shall comply with ISO 8573-1 Class 1 or a more stringent level;
• Microorganism: Although not in ISO Although it is directly stipulated in 8573-1, GMP requires that microbial settling/floating-air-bacteria tests be conducted at regular intervals.

Verification and Continuous Monitoring

Enterprises shall develop a validation protocol for the compressed air system, encompassing installation qualification (IQ), operational qualification (OQ), and performance qualification (PQ). During routine operations, they should equip the system with an online dew point analyzer, a particle counter, and an oil vapor detector, and maintain comprehensive calibration and maintenance records to meet regulatory audit requirements.