Managing the risks of compressed air contamination in a food processing plant is critical. Compressor room drying and filtration is good, but it’s not good enough for a food processing plant. System filtration can reduce the amount of contaminants that are introduced into the downstream distribution system; however, that alone does not meet the requirements of the published GMPs (Good Manufacturing Practices) that address compressed air – nor is it fully effective. Relying solely on system filtration will not significanly lower the risk of food adulteration. In fact, the warm, oxygen rich environment inside the downstream air reservoirs, piping, fittings, and controls are ideal harborage sites for microbial biofilm growth – especially when fed with food grade compressor oils that inevitably migrate downstream. For this reason a number of the published GMPs call for point-of-use filtration to be installed at all points where compressed air either directly or indirectly contacts food or food-contact-surfaces.
The most effective method to prevent potential microbial contamination of the food product from compressed air is to install point-of-use sterile air filtration. The contamination risk associated with compressed air at point of contact can be significantly mitigated with a properly designed compressed air system that employs benchmarked GMPs, a well-designed SSOP (Sanitation Standard Operating Procedure), and maintenance and monitoring programs. Additionally, a system design employing sterile air filtration at point-of-use puts a physical barrier in the air stream guarding against microbial contamination of the food. Combining this system design with an HACCP (Hazard Analysis and Critical Point Control) Prerequisite Program (PRP) formalizing these GMPs and SSOPs creates a cost effective, efficient, and defensible risk management plan.
The diagram below shows the types of contaminants present at each stage of a compressed air system. The first source of contamination is ambient air which can contain water vapor, micro-organisms, atmospheric dirt and oil vapor. The second source of contamination is from the air compressor. The air compressor can introduce water aerosols, condensed liquid water, liquid oil and oil aerosols. The third source of contamination is the air receiver. The air receiver can introduce rust and pipescale. Thus, the total contamination entering the compressed air distribution system includes water vapor, micro-organisms, atmospheric dirt, oil vapor, water aerosols, condensed liquid water, liquid oil, oil aerosols, rust, and pipescale.
This is Part 3 of a 6 Part series on Compressed Air Contamination in Food Plants.
Below are the rest of the links to the series.
Is Your Food Product Safe from Microbial Contamination? Part 4 of 6
Understanding Good Manufacturing Practices for Compressed Air in Food Plants. Part 5 of 6
What's the Best Line of Defense against Microbial Contamination? Part 6 of 6
This series was written by Lee Scott, Market Development Manager, Parker Hannifin