Counterpressure pasteurization systems from Schröter are used to preserve a wide variety of products.
The method ensures that specialties such as brown bread, salmon roe, or meat products remain fresh and flavorful for long periods of time. Along with other well-known companies, Kuchenmeister GmbH also relies on this pasteurization method, which is both product and packaging-friendly.
The industrial bakery company from Soest, Germany, uses several THERMICjets® to preserve its baked goods. The specially developed systems pasteurize products using low-pressure steam in the overpressure range instead of the hot air commonly used in the industry. The advantage of this process is that it increases shelf life without the use of preservatives. Loaves of bread preserved using this method, for example, have a shelf life of up to one year and can be sold worldwide.
The food products are loaded into the pasteurization systems semi-preserved in perforated, heat-resistant euro containers on EUR-pallets. As soon as the loaves of bread packaged in film are inside the system, low-pressure steam is introduced from outside through a valve. This causes the temperature inside to rise to around 80 degrees Celsius at a pressure of over 100 mbar. While the temperature is maintained, the pressure drops due to condensation. This resulting negative pressure is compensated for via compressed air, which is fed into the system through another valve.
The air in the bread’s packaging film expands as a result of the increase in temperature, building up pressure inside the packaging. “To prevent the film from bursting, we have to do something to counteract this pressure,” explains Reza Boozari, project manager at Schröter. This is done in two ways: first, by means of low-pressure steam, as long as the target chamber temperature has not yet been reached. And second, using compressed air fed into the system via another valve, but only after the steam valve has been closed. Since the overpressure ranges from 0.12 to 0.16 bar, the systems are built to be extremely robust and stable. Safety features, such as pneumatically locking lift gates, are also included to ensure that the system runs smoothly.
Thanks to this process, we have significantly reduced the rate of damaged packaging.
CARSTEN WERNER, CTO of Bäckerei Haverland GmbH & Co. KG, a subsidiary of Kuchenmeister GmbH
In 2008, 2014, and 2020, several THERMICjet® PA-3 systems equipped with lift doors were delivered.
The systems from 2008 and 2014 were revised by SCHRÖTER and brought up to the latest state of the art. For example, the control systems were converted and all systems were connected to the existing process visualization. To this end, SCHRÖTER provides values in a data block that the customer can retrieve and process in the process visualization.
