Human Milk Preservation Under Pressure Without Ice Crystallization

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Solution Overview

Problem

Existing methods for preserving human milk, such as high-pressure processing (HPP) and pasteurization, either fail to provide adequate microbiological safety or lead to significant degradation of nutritional and biologically active components, and the equipment is costly and unsuitable for Human Milk Banks (HMBs).

Innovation Solution

A single-step preservation method involving storage of human milk under moderate pressures (60 to 130 MPa) at subzero temperatures (-5°C to -12°C) in an unfrozen state, using a specialized high-pressure vessel, to achieve pasteurization without freezing, ensuring microbiological safety and preserving nutritional and biological values.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If high-pressure processing (HPP) is applied at pressures above 400 MPa to ensure microbiological safety, then microbial inactivation is complete, but biologically active components such as immunoglobulins, lactoferrin, and lysozyme are significantly degraded

Engineering Contradiction:
Improvemicrobiological safetyVSAvoidbiologically active components
Core Design Contradiction:
ReliabilityVSStability of the object's composition

Solution Approach 1:

The patent applies moderate pressures (60-130 MPa) combined with subzero temperatures (-5°C to -12°C) to achieve microbiological safety while preserving biologically active components. This parameter combination creates a synergistic effect where the moderate pressure disrupts microbial cell membranes without denaturing milk proteins, and the subzero temperature prevents ice crystal formation that would damage both microbes and beneficial components.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The invention uses a composite approach by combining pressure and temperature treatments in a unified preservation system. The simultaneous application of moderate pressure and subzero temperature creates a composite preservation effect that achieves microbial inactivation while maintaining the integrity of immunoglobulins, lactoferrin, and lysozyme, overcoming the limitations of using either parameter alone.

Inventive Principle:
Principle #40Composite materials

2Reliability

If conventional pasteurization (HoP) is used to ensure microbiological safety, then microbial contamination is reduced, but nutritional and biological value of human milk is significantly reduced

Engineering Contradiction:
Improvemicrobiological safetyVSAvoidnutritional and biological value
Core Design Contradiction:
ReliabilityVSLoss of substance

Solution Approach 1:

The patent replaces the thermal pasteurization system with a mechanical pressure system combined with subzero temperature treatment. Instead of using heat (62.5°C for 30 minutes) to achieve microbial inactivation, the invention uses moderate pressure (60-130 MPa) at subzero temperatures, which mechanically disrupts microbial cells while preserving heat-sensitive nutrients and biologically active components.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The invention fundamentally changes the preservation parameters from thermal (high temperature) to mechanical-thermal (moderate pressure combined with subzero temperature). This parameter transformation allows achieving the same microbiological safety outcome while avoiding the degradation of nutritional and biological value associated with conventional pasteurization.

Inventive Principle:
Principle #35Parameter changes

3Duration of action of stationary object

If freezing at -20°C is used for storage to extend shelf life, then storage duration is increased, but water crystallization damages nutritional and biological properties

Engineering Contradiction:
Improvestorage durationVSAvoidnutritional and biological properties
Core Design Contradiction:
Duration of action of stationary objectVSStability of the object's composition

Solution Approach 1:

The patent changes the storage temperature parameter from -20°C (which causes ice crystal formation) to a subzero range of -5°C to -12°C. This temperature modification, combined with moderate pressure treatment, prevents water crystallization while extending storage duration to at least 90 days, thereby preserving nutritional and biological properties.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The subzero temperature range (-5°C to -12°C) serves multiple functions: it prevents ice crystal formation that would damage milk components, extends storage duration without freezing, and maintains the efficacy of moderate pressure treatment for microbial inactivation. This multi-functional temperature parameter resolves the contradiction between storage duration and composition stability.

Inventive Principle:
Principle #6Universality (Multi-functionality)

4Reliability

If multiple processing stages (freezing, thawing, pasteurization, re-freezing) are used to ensure safety, then microbiological safety is achieved, but energy consumption increases and valuable components are lost

Engineering Contradiction:
Improvemicrobiological safetyVSAvoidenergy consumption
Core Design Contradiction:
ReliabilityVSUse of energy by moving object

Solution Approach 1:

The patent merges multiple separate processing stages (freezing, thawing, pasteurization, re-freezing) into a single integrated moderate-pressure treatment at subzero temperature. This unified process achieves microbiological safety in one step, eliminating the need for repeated temperature cycling and thermal processing, thereby significantly reducing energy consumption while preserving milk quality.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The moderate pressure treatment at subzero temperature is applied preliminarily to achieve microbial inactivation before storage, eliminating the need for subsequent pasteurization and re-freezing steps. This preliminary action ensures microbiological safety upfront, reducing the total number of processing stages and associated energy consumption throughout the storage period.

Inventive Principle:
Principle #10Preliminary action

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

The method ensures microbiological safety and maintains the nutritional and biological value of human milk for up to 90 days, with minimal alteration to bioactive proteins, reducing the need for freezing and thermal pasteurization stages, and optimizing energy consumption.

Implementation Method 1

storing human milk under selected moderate-pressure and lowered - subzero-temperature conditions

Methodology Applied
Scientific EffectHigh pressure processing: Pressurisation

Implementation Method 2

lowered - subzero-temperature conditions that prevent water crystallization

Methodology Applied
Scientific EffectSupercooling: Supercooling

Data Source

PatentEP4652849A1Mthod of human milk preservation
Publication Date: 2025.11.26 POLITECHNIKA GDANSKA
  • EP4652849A1 patent drawingFigure 1
  • EP4652849A1 patent drawingFigure 2
  • EP4652849A1 patent drawingFigure 3

AI summary

The invention relates to method of preserving human milk that enables to achieve its microbiological safety and additionally maintain its biological and nutritional properties, by storing it under the selected high-pressure/subzero-temperature conditions, in which no water crystallization occurs. The invention has practical applications in Human Milk Banks.