Open Access

Nicole Wente, Christian Zscherpe, Stefanie Leimbach, Paula Mallast, Anne Tellen, Yanchao Zhang, Saskia Schwermann, Volker Krömker

• Late blowing is a prevalent and costly cheese defect caused by clostridia. In organic cheese production, the use of additives that inhibit the growth of clostridia is prohibited. Furthermore, mechanical methods for the removal of clostridia are impractical in organic dairies due to the small batch sizes involved and separation process temperatures (~55 °C) that are incompatible with the standards required for raw milk cheese production. The aim of this study was to investigate whether sufficient spore reduction can be achieved at lower temperatures (10, 35 °C) with a downsized separator (CSC18-01-077, GEA Westfalia) by varying the process parameters to describe the influence on the suitability of the treated milk for cheese production. In addition to spore reduction, total mesophilic bacteria count, the effects of separation on fat and casein losses, and damage to milk fat globules were assessed, as they can affect the yield and cheese quality. A significant reduction (p < 0.01) in spore concentration and total bacteria count in milk was achieved, regardless of the process parameters employed. Casein losses are reduced at 35 °C compared to 55 °C. The extent of fat loss in the sludge at 35 °C was minimal. The reduction in milk fat globule size was significant. Nonetheless, the results of this study demonstrate that a downsized centrifuge can be employed to augment the quality of small-batch raw milk cheese, particularly at a temperature of 35 °C.