EFSA Scientific Opinion - Microbiological Hazards in Food and Feed Production Environments: Key Points to Remember

In January 2024, the European Food Safety Authority (EFSA) released a scientific opinion on the persistence of microbiological hazards in food and feed production and processing environments. This edition of Food Safety & Quality Updates highlights the main points from the publication.

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Relevant Bacterial Hazards Persistent in the Environment

The persistence of microbiological hazards in food and feed production and processing environments is a significant public health concern, posing health risks to consumers and economic losses for manufacturers. Foodborne outbreaks are often linked to strains that persistently colonize the food environment or equipment, typically caused by closely-related genotypes. Hard-to-clean sites and the special abilities of certain microbial strains to withstand stress, desiccation, disinfection, and form biofilms are key factors in their persistence.

• Meat: Listeria monocytogenes and Salmonella enterica are prevalent.
• Fish and Seafood, Dairy, Fruits, and Vegetables: Listeria monocytogenes is a concern.
• Feed and Eggs: Salmonella enterica and Cronobacter are primary threats, with Cronobacter posing a particular risk in infant formula.

Pathogens that persist across various sectors include specific subtypes of Listeria monocytogenes, Salmonella, and Cronobacter. Enhanced environmental monitoring can help reduce the time and cost associated with traditional environmental monitoring methods, thereby helping to mitigate these risks.

Factors contributing to persistence include poor hygienic design of equipment, inadequate cleaning and disinfection, insufficient zoning or hygienic barriers, raw material contamination, high humidity (for Listeria monocytogenes), and issues with aeration, ventilation, or dust (for Salmonella and Cronobacter). Genotypic and phenotypic features of microorganisms also enhance their capacity to persist.

Measures for Monitoring Hazards in the Environment

Sampling and Testing

Designing an effective environmental sampling and testing program involves several critical steps:

1. Identifying Sample Locations: Select areas most susceptible to contamination, such as equipment surfaces, drains, and high-traffic zones.
2. Target Organisms: Focus on pathogens like Listeria monocytogenes, prevalent in dairy environments.
3. Sampling Plan: Plan the frequency, timing, and number of samples to ensure regular monitoring.
4. Testing Protocol: Use robust sampling protocols and precise test methods for accurate results.
5. Evaluation and Follow-up: Record and evaluate results against defined limits and establish clear follow-up actions to promptly address identified issues.

Hygienic Measures

Implementing comprehensive hygienic measures is critical for food safety:

• Water Quality: Ensure clean, potable water in all aspects of production and processing. Regularly test and monitor water sources to prevent contamination.
• Food Safety Culture: Foster a strong food safety culture through employee training, awareness, and commitment to high hygiene and safety standards.
• Cleaning Infrastructure: Invest in effective cleaning infrastructure and ensure thorough sanitation of all surfaces and equipment, with special attention to hard-to-reach areas.
• Technical Maintenance: Regularly maintain equipment to ensure proper functioning and prevent contamination.
• Personnel Hygiene: Enforce strict personal hygiene protocols for employees, including proper handwashing and use of protective clothing to prevent cross-contamination.

By focusing on these key areas, the risk of contamination can be significantly reduced, ensuring a safer production environment and enhancing the overall quality and safety of finished products.

Source Tracking of Contamination

Conducting a thorough root cause analysis is essential for identifying and mitigating factors contributing to persistent microbiological hazards:

1. Probable Factors/Sites: Determine locations and conditions most likely to harbor contamination through detailed inspections and historical data reviews.
2. Appropriate Interventions: Develop targeted intervention strategies based on identified factors and sites, such as changes in cleaning protocols, equipment design modifications, or enhanced personnel training.

Effective source tracking and evaluation of persistence are facilitated by methods capable of subtyping isolates, providing the discriminatory power to track the spread and origin of contaminants. Novel approaches like metagenomics offer significant benefits for source tracking and persistence investigation, allowing comprehensive analysis of all genetic material in a sample to identify otherwise undetectable pathogens.

Regular microbiological testing, including environmental sampling and testing, is essential for identifying contamination sources and detecting persistent hazards. Trend analysis of test results can serve as an early warning system for emerging issues.

Sampling and testing should target specific pathogenic microorganisms, and detailed characterization of isolates is necessary for effective investigations. Typing multiple isolates from each sample helps capture the full diversity of the sample, providing a comprehensive understanding of contamination and its sources.

Incorporating metagenomics and following these steps can enable producers to implement more effective control measures, reducing the risk of contamination and enhancing product safety.

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