Compressed Air Quality in the Food Industry Raises Concerns – Opportunities for Post-Treatment Equipment and Oil-Free Compressors!

Compressed air is widely utilized in food manufacturing sectors including beer, monosodium glutamate, lactic acid, beverage, and food fermentation industries, 

serving as a primary power source and process air supply.

Three Categories of Compressed Air Used in Food Production
Safety and hygiene carry higher priority in food production compared with other industries, requiring stringent control over compressed air quality.
Direct Contact Air
Compressed air that forms part of production and processing and comes into direct contact with food or ingredients.
Examples: Mixing food raw materials, conveying powdered materials, fermentation, cooling and spraying applications all require completely pure compressed air.
Indirect Contact Air
Air that does not touch food directly and is used in packaging, transportation, storage and other processes.
Examples: Blowing PET bottles with compressed air, preparing and opening bags before food filling; air for controlling valves and actuators on automated filling, packaging and bottling production lines.
Non-Contact Air
A portion of compressed air does not come into contact with food, yet different quality standards apply depending on application scenarios.
Examples: Instrument air, air supply for some pneumatic equipment and components.
Compressed Air Standards for Food Production

ISO 8573 specifies corresponding quality standards for compressed air with direct and indirect food contact. It defines limits for contaminants: particle mass concentration below 1 mg/m³, 

particle size less than 1 μm, oil aerosol content below 0.01 mg/m³, and pressure dew point lower than -40°C td.

This translates to requirements for oil-free, dust-free and moisture-free compressed air.
Inadequate removal of moisture and impurities will trigger chemical reactions once contaminants enter food raw materials. This poses health risks to consumers and leads to unnecessary losses for enterprises.
Nevertheless, most domestic food factories can achieve dust-free and oil-free compressed air, yet struggle to eliminate moisture effectively.
Excessive moisture (pressure dew point above -26°C) often triggers pipeline rust and bacterial growth, contaminating food raw materials and increasing defect rates.
Current Status of Domestic End Users
Over more than ten years, we have visited thousands of food factories across China. We found that compressed air at several well-known candy and mooncake manufacturers still contains numerous water droplets and rust particles.
Conditions are even worse at many small-scale processing plants.
The main contributing factors are immature domestic compressed air drying technology and insufficient awareness of compressed air quality standards among users.
Many users purchase equipment in compliance with standards, yet fail to achieve expected drying performance, or experience performance degradation after prolonged operation — a common issue with conventional twin-tower desiccant dryers.
More users only deploy a refrigerated air dryer as the sole drying unit, resulting in substantial liquid water appearing at the point of use.
Proper Configuration of the Compressed Air Station
For consistent product quality, oil-free air compressors are the preferred selection.
Normally, 3 to 4 stages of filtration are required to fully block solid contaminants and oil.
To achieve a steady pressure dew point below -40°C td, a module desiccant dryer must be adopted. If the inlet air temperature is excessively high, a refrigerated air dryer or refrigerated filter dryer may be required as auxiliary equipment.
Conclusion

Although dust and oil contaminants impose greater hazards to food production, filtration technology for such pollutants is highly mature. Only moisture drying technology has achieved breakthroughs in recent years. 

The launch of module drying technology enables sustained and stable pressure dew point performance…