Bacteriophage Phi241 for E. coli O157:H7 Control
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Solution Overview
Problem
Current methods for controlling Escherichia coli O157:H7 in foods are not effective for certain food types and can alter the food's quality, necessitating a safe and effective alternative.
Innovation Solution
The use of a specific bacteriophage, ϕ241, which is isolated from a cucumber fermentation environment with low pH and high salt, to lyse E. coli O157:H7 in foods, maintaining the food's quality while effectively reducing pathogen contamination.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional control methods (pasteurization, radiation, preservatives) are used to control E. coli O157:H7, then pathogen reduction is achieved, but food quality (color, flavor, texture) is altered
Solution Approach 1:
The patent extracts and utilizes a specific biological function (phage lysis) to eliminate the pathogen without applying broad-spectrum controls that harm food quality. The bacteriophage Φ241 specifically targets E. coli O157:H7 through biological lysis, removing only the pathogen while preserving food properties.
Solution Approach 2:
The bacteriophage Φ241 employs self-limiting replication behavior, multiplying only in the presence of its bacterial host and naturally terminating when the host is depleted. This self-regulating mechanism eliminates the need for external control interventions that would compromise food quality.
2Object-affected harmful factors
If phages are used to control pathogenic bacteria in foods, then food quality is maintained, but phage stability under high salinity and low pH conditions needs verification
Solution Approach 1:
The patent characterizes the phage's physiological parameters (optimal pH range of 6.5-8.0, tolerance to 5% NaCl) to understand its stability boundaries. By knowing these parameters, the phage can be effectively applied to foods with moderate acidity and salt content while maintaining operational reliability.
Solution Approach 2:
The phage was isolated from and thrives in the harsh environment of cucumber fermentation (low pH, high salt), converting these previously limiting factors into advantageous selection criteria. This environmental adaptation allows the phage to remain stable in food conditions that would inhibit many other microorganisms.
3Reliability
If phages replicate in foods, then pathogen reduction is enhanced, but phage self-limiting behavior must be maintained to avoid accumulation
Solution Approach 1:
The phage Φ241 exhibits self-limiting replication, automatically terminating its life cycle when host bacteria are depleted. This intrinsic regulatory mechanism ensures efficient pathogen elimination during the active infection phase while preventing uncontrolled phage accumulation that would occur with continuous replication.
Solution Approach 2:
The phage replication cycle operates in distinct periodic phases: adsorption to host, replication, assembly, and lysis. This periodic action pattern ensures rapid pathogen elimination during active infection while naturally pausing when hosts are exhausted, preventing continuous accumulation.
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
ϕ241 achieves significant reductions in E. coli O157:H7 counts in various foods, including vegetables, meats, and juices, ensuring food safety without altering the food's quality, and is stable under high salinity conditions.
Implementation Method 1
contacting the food item with a bacteriophage φ241 under conditions for the bacteriophage φ241 to lyse all or substantially all of the E. coli O157:H7 present in the food item
Data Source
AI summary
Phage Φ241 specific for Escherichia coli O157:H7 was isolated from an industrial cucumber fermentation where both acidity (pH≤3.7) and salinity (≥5% NaCI) were high. A method for preparing a food item at least substantially free of Escherichia coli O157:H7 contamination contacted the food item with a bacteriophage Φ241 under conditions for the bacteriophage Φ241 to lyse all or substantially all the Escherichia coli O157:H7 present in the food item, while Escherichia coli strains other than O157:H7 were not affected. A method for detecting the presence of Escherichia coli O157:H7 by contacting a bacteriophage Φ241 with a food item is also disclosed.