Supercritical CO2 Sterilization of Ground Meat in Extruders
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Solution Overview
Problem
Current methods for sterilizing ground meat are either too expensive, compromise its taste and texture, or involve irradiation, which is unpopular due to concerns over cost, taste, and consumer opposition, and there is a lack of effective methods to prevent E. coli contamination beyond irradiation.
Innovation Solution
The use of supercritical CO2 during the processing of ground meat in a controlled extruder environment, optionally enhanced with chemical sterilization additives, to achieve complete sterilization without affecting the meat's quality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If irradiation is used to sterilize ground meat, then microbial contamination is eliminated, but the product becomes more expensive and changes taste and color
Solution Approach 1:
The patent changes the physical state of CO2 from gaseous to supercritical by adjusting temperature and pressure parameters. This allows the sterilization process to occur in a different state of matter that penetrates meat more effectively without causing the taste and color changes associated with irradiation.
Solution Approach 2:
The patent replaces the electromagnetic radiation mechanism (irradiation) with a fluid penetration mechanism (supercritical CO2). The supercritical fluid physically penetrates the meat matrix and kills microbes through direct contact and cellular disruption, rather than through ionizing radiation, thereby avoiding radiation-induced chemical changes to taste and color.
2Reliability
If irradiation is used to sterilize ground meat, then microbial contamination is eliminated, but production costs increase
Solution Approach 1:
The patent uses CO2, which is a relatively inexpensive commodity chemical that can be easily sourced and replenished. Unlike expensive irradiation equipment with high operational costs, the supercritical CO2 system uses a cheap, readily available fluid that can be continuously cycled through the system.
Solution Approach 2:
The patent recycles the CO2 after use by collecting it from the processing chamber and re-compressing it back to supercritical conditions for reuse. This recovery system significantly reduces the ongoing cost of the sterilization process, making it more economical than irradiation.
3Reliability
If conventional sterilization methods are used, then microbial contamination is reduced, but the meat loses vital taste and texture characteristics
Solution Approach 1:
The patent uses moderate temperature and pressure parameters for supercritical CO2 (typically 31-50°C and 73-300 atm), which are gentler than conventional thermal sterilization methods. This allows effective microbial killing while preserving the delicate taste and texture characteristics of the ground meat.
Solution Approach 2:
The patent replaces thermal sterilization (heat-based) with supercritical fluid sterilization. The supercritical CO2 penetrates the meat matrix and kills microbes through physical disruption of cellular structures, rather than through thermal denaturation of proteins, thereby preserving taste and texture characteristics.
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
This method provides an economical, efficient, and reliable means of sterilizing ground meat, achieving a significant reduction in microbial contaminants while maintaining the product's quality and safety, effectively addressing the challenge of E. coli contamination.
Implementation Method 1
the application supercritical CO2 during the processing of the meat
Data Source
AI summary
A method for sterilizing a ground meat product through the application supercritical CO2 during the processing of the meat by introducing supercritical CO2 into an extruder as the meat passes through the extruder while controlling the pressure and speed at which the meat passes through the extruder to maintain the meat in contact with the supercritical CO2 for a time sufficient to achieve a log reduction in colony forming units of microbial contaminants.