Lactococcal bacteriophages can cause fermentation failures in the cheese production (e.g., Cheddar), especially when the by-product whey (≤10⁹ plaque-forming units mL⁻¹ of bacteriophages) is recycled and added to new batches. Using membrane filtration, the bacteriophage titre in whey can be reduced by 4 log units without protein denaturation. To achieve higher bacteriophage reduction (≥9 log units), we attempted an orthogonal process strategy (combination of different technologies supporting each other). Three representative bacteriophages were inactivated in membrane filtered whey by (i) UV-C irradiation and (ii) heat treatment to achieve additional 5 log units reduction. Thermal treatment was only partially successful, as the varying degrees of heat resistance required, in the worst-case, temperature-time combinations above pasteurisation conditions. In contrast, UV-C treatment required doses of maximally 2.25 J cm⁻² for successful inactivation, thus representing a promising avenue for the establishment of a novel process for the production of “phage-free” whey.

乳球菌噬菌体可导致奶酪生产（例如切达干酪）发酵失败，特别是当副产品乳清（≤10 ⁹菌斑形成单位 mL ^-1噬菌体）被回收并添加到新批次中。使用膜过滤，乳清中的噬菌体滴度可降低 4 个对数单位，而不会发生蛋白质变性。为了实现更高的噬菌体减少量（≥9 log 单位），我们尝试了一种正交工艺策略（不同技术相互支持的组合）。通过 (i) UV-C 照射和 (ii) 热处理使膜过滤乳清中的三种代表性噬菌体灭活，以实现额外的 5 log 单位减少。热处理只是部分成功，因为需要不同程度的耐热性，在最坏的情况下，温度-时间组合高于巴氏杀菌条件。相比之下，UV-C 处理所需的最大剂量为 2.25 J cm ^-2 成功灭活，因此代表了建立生产“无噬菌体”乳清的新工艺的有希望的途径。