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1. Microbiological Risk Characteristics of Near-Expiry Foods

Microbial contamination is a major cause of food spoilage. According to the National Food Safety Standard (GB 7101-2015), pathogenic bacteria (e.g., Salmonella, Staphylococcus aureus) must not be detected in foods, while indicator microorganisms such as coliforms must be controlled within specified limits. However, near-expiry foods may face the following risks during storage and transportation:

1) Environmental Fluctuations: Variations in temperature and humidity may activate dormant microorganisms, accelerating their proliferation. For instance, after a broken cold chain, the lactic acid bacteria count in a certain brand of yogurt increased 50-fold within 24 hours, accompanied by mold overgrowth.

2) Packaging Failure: Leakage in vacuum packaging or degradation of preservatives may lead to aerobic bacterial outbreaks.

3) Cross-Contamination: Mixing fresh produce with pre-packaged foods at retail outlets could introduce exogenous microorganisms.

2. Current Status Revealed by Testing Data

A 2024 third-party sampling inspection of near-expiry foods on the market revealed:

Qualification Rate: 92.3% of samples met microbiological standards, though this represented a 4.7% decline compared to initial shelf-life periods.

High-Risk Categories:

1) High-moisture foods (e.g., ready-to-eat meals, dairy products): 7% of samples had total bacterial counts approaching regulatory limits.

2) Low-acidity foods (e.g., bread, pastries): 3% tested positive for mycotoxins.

Typical Issues: Some imported near-expiry foods exhibited microbiological overgrowth due to incomplete label translations, leading to improper storage conditions.

3. Scientific Logic Behind Shelf-Life Determination

Food shelf-life is not a simple "safe-danger" threshold but a conservative prediction based on accelerated shelf-life testing (ASLT). Examples include:

Dairy Products: At 4°C, shelf-life is typically set at 60% of the time required for total bacterial counts to reach regulatory limits.

Puffed Snacks: When water activity is <0.6, microbiological risks are minimal, and shelf-life is determined primarily by lipid oxidation concerns.
This suggests that near-expiry foods stored under compliant conditions remain theoretically safe, though marginal risks gradually increase.

4. Industry Challenges and Improvement Strategies

Existing Challenges

1) Gaps in Supply Chain Monitoring: Approximately 35% of retailers lack dedicated temperature-control systems for near-expiry foods.

2) Outdated Testing Technologies: Traditional culture methods require 48 hours for results, making them unsuitable for rapid distribution cycles.

3) Insufficient Standard Refinement: Current national standards lack differentiated microbiological limits for near-expiry foods.

Optimization Recommendations

1) Establish Dynamic Monitoring Systems:

1. Promote ATP bioluminescence detection technology for on-site rapid testing (30-minute results).
2. Implement blockchain technology to trace storage environment data.

2) Enhance Standardization:

1. Introduce supplementary testing requirements for high-risk categories during near-expiry stages.
2. Adopt a tiered management approach referencing EU Regulation (EC) No 2073/2005, based on storage conditions.

3) Strengthen Consumer Education:

1. Display real-time test reports via QR codes on packaging.
2. Educate consumers on "immediate discontinuation upon sensory abnormalities."

5. Conclusions and Outlook

Current data indicate that well-managed near-expiry foods maintain high microbiological compliance rates, yet risks in supply chain practices require vigilance. It is recommended to build a collaborative risk management framework involving producers, distributors, and regulators, alongside advancing rapid testing technologies and standard refinement. Looking ahead, the adoption of smart packaging (e.g., time-temperature indicators) will enable more precise and efficient quality control for near-expiry foods.