Baking bread in a cleanroom

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"When it smells enticingly of bread, more people come to our stores," said Gottlieb Duttweiler once. This was the trigger that led to the founding of JOWA in 1931 as a bakery of MIGROS. Today, JOWA includes eight regional bakeries in Switzerland, a pasta factory, a gluten-free products site, a durum wheat mill, two bakeries abroad, and ninety in-house bakeries across Switzerland.

The company JOWA AG, Huttwil, built a new production facility for gluten-free baked goods; the first of its kind in Switzerland. The challenge is to operate a bakery under as germ-free conditions as possible. Gluten-free production requires special hygiene and safety measures. Even the slightest contamination with gluten poses a health risk for individuals with celiac disease.

To achieve the higher air quality conditions of the designated rooms, WESCO AG Cleanroom Technology installed an outdoor air climate system; partly for the fresh air supply for staff, and partly to maintain positive pressure and serve as a replacement for process exhaust air in the cleanroom areas. The outdoor air is dehumidified and channeled through a duct system into the plenum above the cleanroom area. Integrated into the plenum are FFUs (Filter Fan Units), which mix the conditioned outdoor air with recirculated air and deliver it laminar through the particle filters into the cleanroom. Recirculated air flows back into the plenum through return air grilles.

The baked goods are placed directly from the oven into the cooling area (ISO 6 cleanroom class). The products are cooled to the required temperature within one hour. To dissipate this thermal load, ceiling coolers with a cooling capacity of approximately 60 kW are installed in the plenum above the cooling room. The recirculated air in this area is also generated by FFUs, which create a horizontal laminar flow.

The FFUs are equipped with innovative particle filters, which on the one hand have a very low pressure drop (about one-third of conventional particle filters) and on the other hand are water-resistant. The entire system is controlled, monitored, and recorded via the Siemens control system (monitoring of key parameters such as temperature, humidity, pressure).

"We have successfully implemented what we planned with WESCO Cleanroom Technology," said Christoph Keller, Site Manager JOWA Huttwil.