Table_1_High-Temperature Short-Time Pasteurization System for Donor Milk in a Human Milk Bank Setting.docx

Donor milk is the best alternative for the feeding of preterm newborns when mother's own milk is unavailable. For safety reasons, it is usually pasteurized by the Holder method (62.5°C for 30 min). Holder pasteurization results in a microbiological safe product but impairs the activity of many biologically active compounds such as immunoglobulins, enzymes, cytokines, growth factors, hormones or oxidative stress markers. High-temperature short-time (HTST) pasteurization has been proposed as an alternative for a better preservation of some of the biological components of human milk although, at present, there is no equipment available to perform this treatment under the current conditions of a human milk bank. In this work, the specific needs of a human milk bank setting were considered to design an HTST equipment for the continuous and adaptable (time-temperature combination) processing of donor milk. Microbiological quality, activity of indicator enzymes and indices for thermal damage of milk were evaluated before and after HTST treatment of 14 batches of donor milk using different temperature and time combinations and compared to the results obtained after Holder pasteurization. The HTST system has accurate and simple operation, allows the pasteurization of variable amounts of donor milk and reduces processing time and labor force. HTST processing at 72°C for, at least, 10 s efficiently destroyed all vegetative forms of microorganisms present initially in raw donor milk although sporulated Bacillus sp. survived this treatment. Alkaline phosphatase was completely destroyed after HTST processing at 72 and 75°C, but γ-glutamil transpeptidase showed higher thermoresistance. Furosine concentrations in HTST-treated donor milk were lower than after Holder pasteurization and lactulose content for HTST-treated donor milk was below the detection limit of analytical method (10 mg/L). In conclusion, processing of donor milk at 72°C for at least 10 s in this HTST system allows to achieve the microbiological safety objectives established in the milk bank while having a lower impact regarding the heat damage of the milk.

当无法获取母亲自身母乳时，捐赠人乳（donor milk）是早产新生儿喂养的最佳替代方案。出于安全考量，捐赠人乳通常采用霍尔德法（Holder method）进行巴氏灭菌处理：62.5℃下维持30分钟。霍尔德巴氏灭菌虽可获得微生物安全的产品，但会损害诸多生物活性化合物的活性，例如免疫球蛋白、酶、细胞因子、生长因子、激素及氧化应激标志物。高温短时（HTST）巴氏灭菌法被提议作为替代方案，以更好地保留人乳中的部分生物成分，但目前尚无能够在母乳库现有条件下实施该处理的设备。本研究考虑到母乳库场景的特定需求，设计了一款可连续运行、时间-温度组合可调的捐赠人乳HTST处理设备。本研究针对14批捐赠人乳，采用不同温度与时间组合开展HTST处理，并在处理前后分别检测其微生物质量、指示酶活性及人乳热损伤指标，同时将结果与霍尔德巴氏灭菌后的检测结果进行对比。该HTST系统操作精准简便，可对不同体量的捐赠人乳进行巴氏灭菌，且缩短了处理时长与人力投入。在72℃下处理至少10秒的HTST工艺，可有效灭活生捐赠人乳中初始存在的所有营养型微生物，但产芽孢的芽孢杆菌属（Bacillus sp.）可在该处理中存活。经72℃与75℃的HTST处理后，碱性磷酸酶会被完全破坏，但γ-谷氨酰转肽酶（γ-glutamil transpeptidase）表现出更高的耐热性。经HTST处理的捐赠人乳中，糠氨酸（furosine）浓度低于霍尔德巴氏灭菌后的样本，且乳果糖（lactulose）含量低于分析方法的检测限（10 mg/L）。综上，使用本HTST系统在72℃下至少处理10秒，可在达成母乳库设定的微生物安全目标的同时，对人乳热造成的损伤更小。