HACCP Flow Diagrams

HACCP Flow Diagram Symbols & Notation Explained

Standard Symbols and Notation for HACCP Process Flow Diagrams

Using standardised symbols in your HACCP flow diagram is not just good practice - it makes your plan readable by anyone who needs to review it, from your HACCP team members to Environmental Health Officers conducting inspections. While there is no single legally mandated symbol set for HACCP diagrams in the UK, the conventions derived from standard process mapping (ISO 5807) and the Codex Alimentarius guidelines are widely recognised. This guide covers every symbol you are likely to need and explains how to use them consistently.

Key takeaways

Rectangles for process steps, diamonds for decisions, ovals for start/end, parallelograms for inputs/outputs, and cylinders for storage.

Mark CCPs prominently with a star, bold border, or "CCP" label alongside the critical limit.

Number every step sequentially so your hazard analysis can cross-reference specific points.

Include a title block with product group, date, version, and who verified the diagram.

Core Process Symbols

The rectangle is the most common shape and represents a process step - any action performed on the food. Examples include "Receive delivery", "Store at 2-5C", "Dice vegetables", "Cook to 75C core", "Plate and garnish". Every process step where something happens to the food or its environment gets a rectangle. The oval (also called a terminator) marks the start and end of the process. Your diagram should begin with an oval labelled "Start" or with the first receipt of materials, and end with an oval labelled "End" or "Service to customer". Rounded rectangles are sometimes used instead of ovals, but pick one style and stick with it. The diamond represents a decision point where the process branches based on a yes/no question or a measurement. Typical HACCP decisions include "Core temp above 75C?" (yes: proceed to next step, no: continue cooking or discard) and "Delivery temp below 8C?" (yes: accept and store, no: reject). Always label both branches of a decision diamond.

Input, Output, and Storage Symbols

The parallelogram represents inputs entering the process (raw ingredients, water, packaging, ice) and outputs leaving it (waste, trimmings, used packaging). Position inputs on the left side of your main flow and outputs on the right, with arrows showing direction. This makes it easy to see what is added and what is removed at each stage. The cylinder or open-top rectangle represents storage - whether that is a fridge, freezer, dry store, or hot holding unit. Label storage symbols with the required conditions: "Chill store 0-5C", "Freezer -18C or below", "Dry store below 25C". If food moves between storage locations (e.g. from a walk-in chiller to a prep fridge), show both storage steps. Some practitioners use a triangle for temporary delays or waiting periods, such as food resting after cooking or dough proving. If food sits at a controlled temperature for a defined period, this is worth noting because it may represent a hazard point if time or temperature controls fail.

CCP and Monitoring Notation

Critical Control Points should be clearly marked on your flow diagram so they stand out during review. The most common convention is to draw a bold star, asterisk, or "CCP" label next to the relevant step, often with the CCP number (e.g. CCP1, CCP2). Some businesses use a red border or red fill on CCP steps to make them visually distinct. Alongside each CCP marker, note the critical limit: "CCP1: Cook to 75C core" or "CCP2: Chill to below 8C within 90 min". Monitoring points that are not CCPs but are still part of your monitoring programme (operational prerequisite programmes, or oPRPs) can be marked with a different symbol - a circle with "M" inside, or a blue border. This distinction helps your team understand which checks are legally critical and which are good practice. Arrows between steps should be solid lines for the normal flow and dashed lines for corrective action routes (e.g. "reject and return to supplier", "discard", "rewash").

HACCP Flow Diagrams

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Labelling, Numbering, and Annotation Conventions

Number every step sequentially (1, 2, 3...) so your hazard analysis worksheet can reference "Step 7: Cooking" rather than describing the step each time. Place the number inside or immediately above the shape. Keep text inside shapes short - ideally two to four words. Longer descriptions, parameters, and justifications belong in your accompanying HACCP documentation, not on the diagram itself. Add a title block to every diagram that includes: the product group covered, the date the diagram was created, the date it was last verified, the name of the person who verified it, and a version number. This is not optional bureaucracy - an EHO will check whether your diagram is current. If it shows a process you stopped doing six months ago, or omits a new cook-chill process you introduced, that undermines confidence in your entire HACCP system. Use a legend or key if your diagram uses any non-standard symbols. Position the legend in a corner of the diagram so reviewers can decode your notation without guessing.

What to do next

Create a symbol key for your HACCP documentation

Document the shapes and colours your business uses and include this key on every flow diagram. Consistency across all your diagrams prevents confusion.

Review your existing diagrams for missing CCP markers

Check that every CCP identified in your hazard analysis is visibly marked on the corresponding flow diagram with its critical limit.

Add a title block to every flow diagram

Include the product group, creation date, last verification date, version number, and the name of the person who verified it on the shop floor.

Common mistakes to avoid

Mistake

Using inconsistent symbols across different flow diagrams

Instead

Agree on a single symbol set for your business and document it in a legend. If diamonds mean decisions on one diagram and something else on another, your HACCP documentation loses credibility.

Mistake

Putting too much detail inside diagram shapes

Instead

Keep shape text to two to four words. Detailed parameters, temperatures, and time limits belong in the hazard analysis worksheet, not crammed into a rectangle.

Frequently asked questions

Is there a legal standard for HACCP flow diagram symbols in the UK?

There is no UK law mandating specific symbols. However, the conventions from ISO 5807 (information processing flowcharts) and Codex Alimentarius guidelines are widely used and recognised by EHOs. Using standard symbols makes your plan easier for inspectors to read and reduces the chance of misinterpretation.

Should I mark operational prerequisite programmes differently from CCPs?

Yes, it is good practice. Use a distinct marker (e.g. "oPRP" or a different colour) for monitoring points that are important but not true CCPs. This helps your team understand which checks carry the highest consequence if they fail.

Do I need to include packaging and labelling steps on my flow diagram?

If your business packages food for later sale (e.g. takeaway meals, retail packs), then yes. Packaging and labelling are process steps where allergen errors, date coding mistakes, and contamination can occur. If you only plate food for immediate service, these steps are less relevant but the service step should still appear.

HACCP Flow Diagrams