Creating Flow Diagrams and Control Measures for ISO 22000:2005

When implementing ISO 22000:2005, one of the most critical steps is creating detailed flow diagrams that map every stage of your food production process. These visual tools serve as the foundation for identifying potential hazards and establishing control measures that keep food safe from farm to fork. Understanding how to develop comprehensive flow diagrams and conduct thorough hazard analysis is essential for any food business seeking certification.

Why flow diagrams matter in food safety management 🔗

Flow diagrams provide a systematic visual representation of all steps involved in food production. They enable food safety teams to see the entire process at a glance, making it easier to identify where hazards might occur and where control measures need to be implemented. ISO 22000 requires organizations to build and operate a food safety management system within a well-defined framework that starts with understanding every aspect of the production process.

A well-designed flow diagram includes sequential process steps, all materials entering or leaving the process, key processing conditions like time and temperature, major equipment used at each step, and potential cross-contamination points. This comprehensive view allows teams to conduct effective hazard analysis and determine appropriate control measures.

Building comprehensive flow diagrams 🔗

Creating an effective flow diagram requires more than simply listing process steps. Each step must be accompanied by detailed descriptions that provide sufficient information for hazard analysis. For instance, if your process includes a receiving step for raw materials, the description should specify how materials are delivered, what quality checks are performed, acceptance criteria, and temporary storage conditions.

The flow diagram should incorporate all inputs and outputs, including ingredients, packaging materials, water, compressed air, and waste streams. Process flow charts for ISO 22000 purposes should definitely include all relevant inputs and outputs in addition to operational process steps, as this information is crucial for complete risk evaluation.

Process parameters such as critical temperatures, holding times, pH levels, and other factors must be clearly documented. Equipment details should specify the type and capacity of machinery used at each stage. Cross-contamination points where raw and processed products might interact require special attention and clear marking on the diagram.

On-site verification of flow diagrams 🔗

After creating initial flow diagrams, the food safety team must physically walk through the production facility to verify accuracy. This on-site confirmation ensures that the diagram reflects actual operations, not just theoretical processes. During verification, teams often discover steps that were overlooked or find that actual practices differ from documented procedures.

Conducting hazard analysis at each process step 🔗

Once flow diagrams are verified, the next step is comprehensive hazard analysis. Critical control points should be identified on the process flow diagram as those points where lack of control could cause, allow, or contribute to a microbiological hazard in the final product.

Hazard analysis involves systematically identifying potential food safety hazards at each process step. Hazards typically fall into three categories: biological hazards including bacteria, viruses, parasites, and fungi that can cause foodborne illness; chemical hazards such as pesticide residues, allergens, cleaning chemicals, and heavy metals; and physical hazards like glass, metal, plastic, stones, or bone fragments that can cause injury.

The risk assessment methodology 🔗

For each identified hazard, a risk assessment must be performed. This involves evaluating both the severity of the hazard and the likelihood of its occurrence. The procedure provides guidelines to identify food hazards and evaluate risks to quality and safety, analyzing hazards to assess their likelihood of occurrence and potential to render food unsafe.

Severity considers the potential health impact if the hazard reaches consumers. High severity hazards include those that can cause serious illness or death, such as pathogenic bacteria like Salmonella or E. coli. Medium severity hazards might cause illness but are typically not life-threatening. Low severity hazards cause minor discomfort or have minimal health impact.

Likelihood assessment examines how probable it is that the hazard will occur at that specific process step. This considers factors such as the nature of raw materials, processing conditions, equipment design, and operational practices. Historical data, scientific literature, and industry knowledge all inform likelihood determinations.

Determining significant hazards 🔗

Not all identified hazards require the same level of control. The food safety team must determine which hazards are significant based on the combined assessment of severity and likelihood. A hazard is typically considered significant if it has high severity regardless of likelihood, or if both severity and likelihood are at medium levels.

This significance determination guides decisions about control measures. ISO 22000 requires that all significant hazards be controlled through either the HACCP plan or operational prerequisite programs, with the food safety team determining which hazards need control, to what extent, and which combination of control measures is required.

Planning and implementing control measures 🔗

Control measures are actions or activities used to prevent, eliminate, or reduce food safety hazards to acceptable levels. These can include time and temperature controls, cleaning and sanitation procedures, supplier approval programs, metal detection, and proper storage conditions.

Control measures are categorized into three types: Prerequisite Programs (PRPs) which are basic conditions and activities necessary to maintain a hygienic environment; Operational Prerequisite Programs (OPRPs) which are control measures essential to prevent or reduce significant hazards but where action criteria allow effective process control; and Critical Control Points (CCPs) which are process steps where control is essential to prevent or eliminate a food safety hazard.

Practical example: Aseptic mango pulp processing 🔗

To illustrate these concepts, consider a simplified flow chart for aseptic mango pulp processing. The process typically includes these sequential steps: receiving raw mangoes, initial washing, sorting for quality, controlled ripening, second washing, peeling and cutting, pulping, refining to remove fibers, homogenization, de-aeration, pasteurization, rapid cooling, aseptic filling, packaging, and storage/dispatch.

Each step in this flow diagram requires detailed description. For example, the sorting step might be described as: “Mangoes are manually sorted on stainless steel sorting tables by trained operators. Sorting is based on ripeness, size, and visible defects. Overripe, underripe, or damaged fruits are removed. Sorting is performed under white LED lighting at minimum 540 lux to ensure proper visibility. Sorted mangoes are transferred to plastic crates for further processing.”

Sample hazard analysis for fruit receiving 🔗

Let’s examine a detailed hazard analysis for the receiving step. Biological hazards at this step include pathogenic bacteria such as Salmonella and E. coli that may be present on fruit surfaces. The severity is high as these can cause serious illness, while likelihood is medium depending on agricultural practices and growing conditions. This combination makes it a significant hazard requiring control.

Chemical hazards include pesticide residues from agricultural applications. Severity is medium depending on the specific pesticide and residue level, with medium likelihood based on farming practices. Control measures include supplier certification programs, periodic testing, and documented specifications for maximum residue limits.

Physical hazards such as soil, stones, or foreign materials attached to fruits have low to medium severity but medium likelihood. Control measures include visual inspection during sorting and washing procedures designed to remove surface contaminants.

Based on this hazard analysis, control measures for receiving might include supplier approval and monitoring programs, certificates of analysis for pesticide testing, visual inspection procedures with reject criteria, and proper storage to prevent contamination or pest access.

Critical control points in aseptic processing 🔗

In the mango pulp example, several steps would likely be identified as CCPs. Aseptic processing involves thermal sterilization at high temperatures for short periods, typically achieving commercial sterility with minimal impact on product quality.

Pasteurization is a critical control point where biological hazards are controlled through thermal destruction of pathogenic microorganisms. Critical limits include specific time-temperature combinations validated to achieve required microbial reduction. Monitoring involves continuous temperature recording with automated controls. Aseptic filling prevents recontamination of the sterile product, with critical limits including maintaining sterile conditions and proper package sterilization. Metal detection serves as a CCP for physical hazards, with sensitivity levels and reject mechanisms as critical limits.

Maintaining and updating flow diagrams 🔗

Flow diagrams and hazard analyses are not static documents. They must be reviewed and updated whenever process changes occur, new hazards are identified, or control measures are modified. Regular verification activities confirm that flow diagrams remain accurate and control measures remain effective.

The food safety team should establish a schedule for periodic review of all flow diagrams and hazard analyses, even when no changes have occurred. This ensures the system remains current with scientific knowledge, regulatory requirements, and best practices.

What do you think? How often should your organization review and verify its process flow diagrams to ensure they reflect current operations? What challenges have you encountered when identifying significant hazards and determining appropriate control measures in your food safety management system?

References

1. https://www.dnv.us/services/iso-22000-food-safety-management-5173/
2. https://www.ifsqn.com/forum/index.php/topic/19857-example-process-flow-diagram-required-in-haccp-iso-22000/
3. https://www.fda.gov/inspections-compliance-enforcement-and-criminal-investigations/inspection-guides/aseptic-processing-and-packaging-food-industry
4. https://www.researchgate.net/publication/332849012_HAZARD_ANALYSIS_AND_RISK_ASSESSMENT_ISO_22000_PS_3733_Halal_Food_Management_System
5. https://link.springer.com/article/10.1007/s00769-019-01409-4
6. https://www.britannica.com/topic/food-preservation/Aseptic-processing