Food Pasteurization in Sealed Packaging With Supercritical CO2

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Solution Overview

Problem

Existing pasteurization processes, such as thermal, high hydrostatic pressure, and supercritical CO2 methods, cause significant changes in food texture, flavor, and are costly or require expensive aseptic packaging, leading to spoilage and reduced shelf-life.

Innovation Solution

A pasteurization process using a packaging filled with a gas mixture, including carbon dioxide, subjected to pressures between 4 MPa and 20 MPa and temperatures between 25°C and 50°C, maintaining CO2 in a supercritical state for microbial inactivation, with optional addition of natural antioxidants.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If thermal pasteurization is used to inactivate microorganisms, then microbial safety is improved, but food texture, color and flavor are deteriorated

Engineering Contradiction:
Improvemicrobial safetyVSAvoidfood texture, color and flavor
Core Design Contradiction:
ReliabilityVSStability of the object's composition

Solution Approach 1:

The invention changes the physical parameters of the treatment process by using high pressure (50-10000 MPa) instead of high temperature, and by controlling the phase state of CO2 (supercritical or dense phase) to achieve microbial inactivation while preserving food quality attributes

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The invention utilizes phase transitions of CO2, specifically maintaining it in supercritical state (above critical point: 31.1°C, 7.38 MPa) or dense phase to achieve pasteurization. The phase state change allows CO2 to penetrate food matrix effectively while providing bactericidal action without thermal damage

Inventive Principle:
Principle #36Phase transitions

2Reliability

If high hydrostatic pressure (HHP) is used to pasteurize food, then microbial inactivation is achieved, but food products are spoiled and reduced to pulp

Engineering Contradiction:
Improvemicrobial inactivationVSAvoidfood structure integrity
Core Design Contradiction:
ReliabilityVSStability of the object's composition

Solution Approach 1:

The invention optimizes the pressure parameter range to 50-10000 MPa (preferably 100-500 MPa for supercritical CO2 treatment) and controls temperature and CO2 phase state to achieve effective pasteurization without the extreme pressures that cause food structure collapse. The combination of moderate pressure with supercritical CO2 provides synergistic bactericidal action

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The invention uses a composite treatment approach combining high pressure with supercritical or dense phase CO2, creating a composite physical-chemical environment that enhances microbial inactivation while preserving food structure, unlike HHP alone which uses only mechanical pressure

Inventive Principle:
Principle #40Composite materials

3Reliability

If supercritical CO2 is applied directly to food before packaging, then pasteurization is achieved, but product contamination risk increases

Engineering Contradiction:
Improvepasteurization effectivenessVSAvoidproduct contamination risk
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The invention performs pasteurization treatment before packaging by applying supercritical or dense phase CO2 to the food product in a controlled manner, then allowing complete depressurization and CO2 removal before sealing. This preliminary treatment eliminates microbial contaminants before packaging, reducing the need for expensive aseptic packaging systems

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The invention allows CO2 to be completely vented and removed from the food product after pasteurization treatment. The CO2 is discarded from the treatment chamber, and the food is allowed to return to atmospheric pressure and ambient conditions before packaging, eliminating contamination risk from residual CO2

Inventive Principle:
Principle #34Discarding and recovering

4Reliability

If high pressures higher than 50 MPa are used for pasteurization, then effective bactericidal effect is achieved, but many types of food products are spoiled

Engineering Contradiction:
Improvebactericidal effectVSAvoidfood product quality
Core Design Contradiction:
ReliabilityVSStability of the object's composition

Solution Approach 1:

The invention changes the approach by using CO2 in supercritical or dense phase state at pressures of 50-10000 MPa (optimally 100-500 MPa), which provides effective bactericidal action through both pressure effects and CO2's solubility and penetration properties, while the controlled phase state prevents food structure damage that occurs with HHP alone

Inventive Principle:
Principle #35Parameter changes

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

Effectively inactivates microorganisms while preserving food texture and color, reducing CO2 consumption by over 98%, and enabling cost-effective industrial-scale implementation.

Implementation Method 1

supercritical carbon dioxide (CO2) and nitrous oxide (N2O) are able to inactivate microorganisms and enzymes

Methodology Applied
Scientific EffectSupercritical fluid: Supercritical Fluid

Implementation Method 2

employs hydrostatic pressures from 500 MPa to 10000 MPa and temperatures close to room temperature

Methodology Applied
Scientific EffectHigh pressure process: Pressurisation

Data Source

PatentEP3675652B1Method for food pasteurization
Publication Date: 2025.08.20 UNIV DEGLI STUDI DI PADOVA
  • EP3675652B1 patent drawingFigure 1a~1c
  • EP3675652B1 patent drawingFigure 1d~1f
  • EP3675652B1 patent drawingFigure 2

AI summary

A method for treating food where inside a packaging, made of a material configured for containing a gas-mixture, a food product and a gas mixture including at least carbon dioxide are inserted. Then, on the sealed packaging a uniform pressure, between 4 MPa and 20 MPa, is applied to compress the food. During application of the pressure, the packaging is maintained at a temperature between 25° C. and 50° C.