High-Temperature Short-Time Preserves Human Milk's Bioactive Proteins and Their Function Better Than Pasteurization Techniques With Long Processing Times

Abstract

Donor human milk is generally processed by holder pasteurization (HoP) at 62. 5°C for 30 min. This temperature-time combination is sufficient for eliminating pathogens in donor milk, but also negatively affects several bioactive milk components. Long heating up times may further affect the bioactive properties of pasteurized milk. High-Temperature-Short-Time (HTST), a treatment with shorter processing times (72°C for 15 sec), was investigated as a suitable alternative to HoP. In addition, pasteurization methods that follow the same temperature regime but with varying heating up times were compared. Human milk samples from four different donors were combined into one pool, which was then used to perform all analyses. The effects of these methods on the levels and functionality of immunoglobulin A, lactoferrin, lysozyme and bile salt-stimulated lipase, were evaluated with LC-MS/MS-based proteomics and activity assays, while the pasteurization efficacy was evaluated with an alkaline phosphatase test. HoP, a treatment with long processing times, times, caused the highest reduction in all proteins studied (reduced by 50–98%). Compounds such as lactoferrin and bile salt-stimulated lipase that are more sensitive to heat treatments were better retained with HTST, but their levels and functionality were still significantly lower than those of untreated donor milk (52 and 81% reduction of lactoferrin and bile salt-stimulated lipase activity, respectively). Our findings showed that a treatment with considerably shorter processing times, such as HTST, may reduce the thermal damage caused to the bioactive proteins compared to HoP, without affecting pasteurization efficacy. Since the vast majority of the donor human milk banks that are currently operating on a global level apply HoP to donor milk, our findings may provide relevant information for the optimization of donor milk processing.

Holder Pasteurization: Comparison of Water-Bath and Dry-Tempering Devices

“…These methods were developed with the aim to achieve antiviral or antibacterial efficacy approximating the gold standard HoP, while at least weakening its detrimental impact on HM ( 15 ). Reports of increased protein retention by comparing HTST devices at 62–87°C plateau temperatures and 1–18.5 s holding times to HoP are in line with our findings ( 14 , 16 – 19 ). Unlike those experimental continuous flow devices, we utilized a commercially available device originally designed for cytomegalovirus inactivation ( 7 ).…”

“…By shortening the ramp time and thus heat exposure of HM proteins, Kontopodi at al. observed a tendency toward improved protein retention in milk that was rapidly preheated with an experimental HTST device before being Holder-pasteurized ( 14 ).…”

Effects of High-Pressure Processing, UV-C Irradiation and Thermoultrasonication on Donor Human Milk Safety and Quality

“…The Filter Aided Sample Preparation (FASP)method was carried out as previously reported ( 26 , 27 ). Briefly, milk serum samples were diluted with 100 mM Tris (pH 8.0) to a protein concentration of 1.0 μg/μL.…”

Evaluating UV-C sensitivity ofCoxiella burnetiiin Skim Milk using a Bench-Scale Collimated Beam System and Comparative Study with High-Temperature Short-Time Pasteurization

“…The heat challenge studies were conducted using a lab-scale HTST pasteurizer (Kontopodi et al, 2022). The pasteurizer consists of 3 main sections, as shown in Figure 2 a pre-heating section (77 ºC), a holding section (72 ºC for 15 sec), and a cooling unit.…”