Compressed air quality in the meat industry

Reliably monitor the dew point, residual oil and particles – wherever hygiene, product safety and audit evidence are crucial.

Compressed air is a key operating medium in the meat industry. It may come into direct contact with unpackaged meat or influence processes close to the product. What matters here is not only the treatment in the compressor room, but also the actual quality at the point of use.

Three parameters are particularly relevant for assessing compressed air quality: pressure dew point, residual oil and particles. The measurement location and monitoring logic vary depending on the specific application.

Dew point: measure centrally after treatment

The pressure dew point is an important parameter for the hygienic assessment of compressed air, as humidity can promote the growth of micro-organisms. The growth of microorganisms in compressed air slows as the pressure dew point falls and comes to a halt below –26 °C (BCAS R102-1). For this reason, a Class 2 pressure dew point of –40 °C is often targeted.

Residual oil: monitor centrally before condensation forms

The residual oil content should also be monitored centrally following treatment. The reason for this is that the air is significantly warmer after passing through the compressor than it is in the distribution network and in the production areas. In meat processing, temperatures are often around 10 °C, and in cold stores they are significantly lower still.
This increases the risk of gaseous oil components condensing and accumulating in the cooler network. This is precisely what must be avoided, as it can lead to oil carry-over. Centralised residual oil measurement is therefore an essential component of ensuring hygienically safe compressed air.

Particles: measure at the sampling point

Particles must be assessed differently from dew point and residual oil. They may not only originate from the generation process, but may also arise within the distribution network itself, for example as a result of corrosion, abrasion or filter problems. This is why the measurement of particles at the point of use is particularly informative.
The cleanliness in the compressor room is therefore not automatically the same as the cleanliness at the consumer point. For a reliable assessment, the actual conditions must be taken into account at the point where the compressed air is used in the process.

Audit and verification: risk-based and by withdrawal point

At the latest during an audit, compressed air quality becomes a subject requiring inspection. Current standards require a risk-based assessment of process media. The following applies to compressed air that comes into direct contact with foodstuffs or primary packaging: it must not pose a risk of contamination and must be monitored.
It is important to note that the standards do not generally specify fixed numerical values, but require a justified specification for each extraction point. In practice, this results in: 

• a comprehensive register of all extraction points,
• an assessment of the type of contact,
• the specified purity class,
• a test plan specifying the point of measurement, method and frequency,
• and a defined procedure in the event of deviations.

In this way, compressed air quality is not only technically controlled but also documented in a manner suitable for audit purposes.

Contamination: where it can occur

Compressed air may already be contaminated at the point of intake, or may become contaminated during compression, treatment, storage and distribution. The main contaminants of concern are particles, water, oil and micro-organisms.

It is particularly important to note that the quality in the compressor room is not automatically the same as the quality at the point of use. Pipes, storage tanks, filters, hoses and points of use can subsequently alter the air quality in the network. Therefore, compressed air must be assessed at the point where it actually plays a role in the process.

Relevant sources and standards

The following standards are particularly relevant to the compressed air quality in the meat industry:

  • ISO 8573-1:2010 – Purity classes for compressed air
  • ISO 8573-2 to -9 – Test methods for humidity, oil, particles, free water and microbiological contamination
  • VDMA Standard Sheet 15390-2:2018 – Guidelines for compressed air purity in the food and pharmaceutical industries
  • IFS Food version 8 – Requirements for process media and compressed air in direct contact with food or primary packaging
  • BRCGS Food Safety Issue 9 – Monitoring of compressed air in direct contact with the product at the point of use
  • SQF Food Safety Code Edition 10 – Risk-based monitoring of clean compressed air
  • FSSC 22000 version 6 / ISO/TS 22002-1 – Requirements for utility media and the assessment of compressed air applications
  • Regulation (EC) No 852/2004 – Food hygiene
  • Commission Communication 2022/C 355/01 – Guidelines on HACCP principles

Conclusion

Compressed air quality in the meat industry is a matter of hygiene, process control and compliance. Three factors are crucial: centrally monitoring the dew point and residual oil content after treatment, checking for particles at the point of use, and clearly documenting the requirements for each application. In this way, compressed air becomes a controlled component of the hygienic process chain.