FOOD PROCESSING & PACKAGING
Scott Grimes, Sector Specialist at
Donaldson, outlines the importance of effective filtration that meets food safety standards for sterile compressed air and culinary steam
T
here is increasing scrutiny being placed on sterile compressed air and culinary steam in the food and beverage processing industry. Filtration systems must therefore comply with strict food safety standards globally. While the language surrounding the various standards differs slightly, they all require that food processors identify and manage compressed air and culinary steam as potential hazards to product safety and quality.
Multi-stage filtration for sterile compressed air
High purity compressed air is an indispensable part of the food manufacturing process. However, unfiltered air contains undesirable contaminants that must be removed from the manufacturing process. A well-designed and managed filtration system is therefore essential for maintaining product safety and meeting regulatory requirements. Years of engineering and testing in food processing have proven that a multi-stage filtration system is ideal.
Filter number one removes large amounts of water and rust that contaminate the lines. It should be composed of appropriate filter media to prevent the filter from becoming blocked too quickly.
Filter number two must have greater capture efficiency than the first filter as it is responsible for removing all remaining water and oil aerosols, as well as any particles that may have penetrated the first filter. It should ideally incorporate a pleated media structure as this has greater media surface area, which reduces the pressure loss and increases service life by providing more dirt holding area than non-pleated media. The final filter captures microorganisms and reliably withstands the extreme conditions of steam sterilisation. Filtration media made of PTFE membrane or borosilicate is often the best choice because it is highly resistant to steam and can be very tightly controlled to produce a bacterial-retentive structure for processed food and beverages that remains
WHY FILTRATION IS CRITICAL TO FOOD SAFETY
effective over the entire service life. Since this filter should not encounter any dirt or oil, it is recommended to choose a version that can tolerate a high number of sterilization cycles. This filter should be rated at >99.9999998% at 0.2 microns because small size particles are the most challenging to capture.
Two-stage filtration for culinary steam
Culinary steam is direct injected into food for cooking or used indirectly to clean and sterilise vats, mixers, conveyors, and other equipment used in the food-production process. The most referenced and specific definition of culinary steam comes from the 3-A Sanitary Standards, Inc. document - Accepted Practices for a Method of Producing Culinary Steam, Number 609. This defines "steam of culinary quality" as steam that is: • Free of entrained contaminants. • Relatively free of water in liquid form. • Suitable for use in direct contact with food products, other comestibles, or product- contact surfaces.
The primary safety concern is that
unfiltered steam can contain contaminants, including rust and dirt, that could end up in the food product. Unfortunately, a major source of contamination is often the steam generation process itself, especially in systems where excess steam is condensed, recirculated, and reused in the process. This “recirculated condensate” can be contaminated with pipe scale and suspended solids, as well as oils and metallic debris shed by the pumps in the recirculating system. If the steam is not filtered before use, these contaminants can make their way into or onto the food product.
Filtering culinary steam will also significantly reduce plant maintenance costs. Unfiltered steam can coat heat exchangers, producing an undesirable insulating effect which can slow heat transfer and increase production
18 NOVEMBER/DECEMBER 2025 | PROCESS & CONTROL
Verifying production processes As interest over consumer and product safety standards continue to grow, food and beverage manufacturers around the globe can expect increased attention on the food safety standards and processes within their facilities. This includes ensuring that compressed air and culinary steam filtration systems meet the latest standards. Verifying that production processes comply with current regulations and standards will help you manage risks in your process. It will also help to support product and brand integrity, which is crucial for maintaining consumer trust and brand loyalty in a competitive and highly inspected industry.
Donaldson
www.donaldson.com/process
times. Robust filtration systems will also remove dirt, rust and scale that can abrade pumps, valves and other hardware, causing premature equipment failure.
To be assured of generating compliant culinary steam during food processing, there are two critical stages of the filtration system - a point-of-use culinary steam filter and a pre-filter or entrainment separator. The entrainment separator must remove ≥10 µm particles and include a condensate trap. It should be installed upstream of the culinary steam filter.
The culinary steam filtration should be installed at all points-of-use because any piping downstream of your final filter could create additional opportunities for contaminants to enter the system. This should remove 95% of particulates two microns in size and larger. Filter housings must be 300- series stainless steel, with sanitary welds and finishes, and be readily accessible for inspection and cleaning. A sanitary check valve should be installed downstream to prevent backflow contamination.
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