Hygienic Design for Food & Processing Industries: From Cleanability to Cost Savings

Jürgen Hofmann unlocks a glass cabinet.

“Look at this,” he says. Inside a length of stainless steel piping, a 90‑degree branch ends in a bolted cover that once housed a sensor. The tube was sealed, leaving a dead end that cannot be reached by cleaning liquid, and its coarse finish makes it a haven for bacteria.

Hofmann’s mission is clear: design machines that make hygiene-critical operations effortless and effective. Cleanability is his mantra.

He is stepping into a project led by the Fraunhofer Institute for Process Engineering and Packaging in Germany. The initiative includes an online portal, HygienicProcessing.com, a comprehensive hub of hygienic‑design knowledge, practical tips, literature links, and a network of experts.

For nine years, Hofmann has been an academic assistant in the Department of Process Engineering at the Technical University of Munich’s Weihenstephan campus, a leading center for food‑related research.

“Hygienic design matters wherever equipment must stay clean,” he explains. “That includes pharmaceuticals, cosmetics, and even paint.”

Cleaning in food processing is a liquid‑driven operation. The liquid must flow unimpeded through every pipe, valve, tap, and pump. Hofmann’s job is to eliminate gaps, holes, grooves, or dead zones that could harbor microorganisms. Smooth surfaces, correctly angled curves, and perfectly fitted seals and gaskets are essential.

In the dairy sector, for instance, seals were historically set back from the inner pipe surface, creating a gap that became a breeding ground for microbes. Although such equipment remains in use, Hofmann has helped redesign it so the seal sits flush with the pipe wall, dramatically improving cleanability.

Investment decisions, however, are often siloed. “There’s a separate budget for capital and another for maintenance, but by adopting hygienic design you can save 25–50 % over the equipment’s lifetime,” he notes. “And if contamination occurs, the costs can be astronomical.”

Not all foods demand the same level of scrutiny. Beer, for example, is less critical than dairy because alcohol suppresses pathogenic bacteria—though alcohol‑free beer presents its own challenges. Dairy contamination can be more severe, and recent consumer trends toward preservative‑free products heighten the need for stringent hygiene.

Hofmann’s university hosts a cleanability testing center that follows the European Hygienic Engineering & Design Group (EHEDG) standard. The test involves running a standardized contaminant through the part and a reference pipe, applying a 1 % alkaline detergent, and then culturing the residue on agar to quantify remaining contamination.

“I enjoy this work because it makes a tangible difference,” Hofmann says. “We influence processes, set new trends, and it’s gratifying when a company builds a machine from our concepts.”

Trelleborg Sealing Solutions collaborates closely with the University of Munich and has focused research on sealing designs that meet Hofmann’s hygienic principles.

“We recommend optimal seal configurations for food, beverage, and pharmaceutical processing,” says Burkhard Ledig, Technical Manager CPI Development Europe. “A recent example is the Turcon Variseal Ultra‑Clean.”

Variseal is engineered for processing systems, compatible with almost all chemical media, with superior wear resistance, friction characteristics, and the ability to withstand extreme temperatures. Traditional PTFE seals lack elasticity, requiring a spring to energize the seal. That spring creates a dead space where bacteria can accumulate.

“Therefore, we developed an alternative,” Ledig explains. “The Turcon Variseal Ultra‑Clean encloses the activating spring within a Turcon case, eliminating dead space and preventing bacterial buildup—essential for food, beverage, and pharmaceutical manufacturers.”

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A Pub as a Classroom

The Department of Process Engineering is unique in having a pub that doubles as a teaching laboratory. Charly’s Pils Pub, named after Professor Karl Sommer, showcases cutting‑edge brewery hygiene. Its bar features a range of taps that let brewery representatives and pub owners compare which systems best suit various beers, and it displays the latest cleaning technologies.

“Many pub owners hesitate to invest in tap units and often lack hygiene training,” Hofmann notes. He sometimes orders bottled beer, without a glass, when visiting pubs to illustrate the risks. Yet the brewing industry has progressed dramatically. “Back in my childhood, we lived next to an open‑fermenting brewery, and the first glass of beer was discarded because of overnight bacterial buildup,” he recalls. “Now large breweries aim for a shelf life of 12–18 months, demanding higher process technology and hygiene standards.”

This article was provided by Trelleborg Sealing Solutions. For more information, visit www.trelleborg.com.