High-Temperature Short-Time Pasteurization System for Donor Milk in a Human Milk Bank Setting

Abstract

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.

Effect of HTST and Holder Pasteurization on the Concentration of Immunoglobulins, Growth Factors, and Hormones in Donor Human Milk

“…Globally, HTST treatments were associated to a significantly higher preservation of, at least, some of the biologically active compounds tested in this study. The effect of this HTST system on the microbiological quality of DHM had been evaluated previously ( 26 ).…”

“…Another aliquot (120 mL) was transferred to a glass bottle (150 mL), and subjected to HoP (62.5°C for 30 min) and fast cooling at 4°C in shaking water baths (Jeio Tech BS-21, Lab Companion, Oxfordshire, UK) following the current HMB protocol. The rest of the production batch was HTST-processed at a fixed temperature (70, 72, or 75°C) and different times (5, 10, 15, 20, and 25 s) using the HTST equipment described by Escuder-Vieco et al ( 26 ). A total of 8 batches were HTST-processed at 70°C, 9 at 72°C, and 7 at 75°C.…”

“…Nevertheless, previous studies involved a low number of samples or the use of experimental systems that may be unsuitable for routine use in HMBs. In this context, a continuous HTST system to pasteurize DHM in the HMB operating environment was designed and validated recently ( 26 ). This HTST equipment was conceived to ensure accurate, simple and flexible operation at a HMB setting where the available amount of DHM may be variable.…”

“…This HTST equipment was conceived to ensure accurate, simple and flexible operation at a HMB setting where the available amount of DHM may be variable. In addition, processing of DHM at 72°C for, at least, 10 s in this HTST system allowed to achieve the microbiological safety objectives currently established in HMBs ( 26 ).…”

Improving Pasteurization to Preserve the Biological Components of Donated Human Milk

“…However, although a better preservation of several components like IgA and lactoferrin has been described, bile salt-stimulated lipase (BSSL) activity is almost completely eliminated ( 19 – 21 ). Two alternative prototypes suitable for use in an HMB have been recently described ( 22 , 23 ).…”