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Don’t get caught out using the old Codex decision tree…

In this post we’ll go through the risk of using the wrong decision tree.  I’ve also created a free prerequisite template for you, you can get your copy by clicking the button at the bottom of this post.

There are two types of the codex decision tree, the original one and a more modern one that’s been adapted to include the fact that we now use prerequisites to manage the fundamental practises that manage how we make food safely.

When codex was originally developed in the 1990’s, it contained the 7 principles:

Principle 1: list the potential hazards, conduct a hazard analysis and consider the control measures
Principle 2: determine the critical control points (CPPs)
Principle 3: establish critical limits for each CCP
Principle 4: establish a monitoring system
Principle 5: establish the corrective action to be taken if monitoring shows that the CCP is out of control
Principle 6: establish verification procedures
Principle 7: set up documentation of the procedures and records

Although codex talks about control measures in principle 1, it doesn’t mention prerequisites. When Codex HACCP was first introduced, many manufacturers had loads of CCPs, because of a lack of prerequisites. Since then, prerequisites have developed massively and most HACCP plans today have a good set of prerequisites that manage food safety, quality and legality of the products we produce. This in turn, has reduced the need to have as many CCPs.

For this reason the original Codex decision tree was adapted to include an addition question, question 1 ‘is this hazard managed by a prerequisite programme’.

Original decision tree

Codex decision tree

New version of the decision tree


Codex decision tree

Campden Guideline 42

I would strongly recommend that you use the updated version of the decision tree and I’ll explain why…

Let’s take the example of ‘Growth of staphylococcus aureus in the dispatched finished product caused by ineffective temperature control during storage’ at the process step of “storage prior to dispatch.”

If you use the original Codex decision tree your assessment would look like this:

Question 1: ‘Do control measures exist for the identified hazard?’
Answer: – Yes, we have temperature control so we’d move to question 2.

Question 2: ‘Is the process step specifically designed to eliminate or reduce the likely occurrence of the hazard to an acceptable level?’
Answer: – Yes, we store the product in chilled conditions to control the growth of pathogens like Staphylococcus aureus. Therefore the chilled storage becomes a CCP.

Today, the chilled storage of product is widely recognised as being managed by prerequisites, as we have good basic controls in place, the need to control it as a CCP is overkill.

Because of this reason I’ve seen many HACCP plans where this exact hazard has been assessed through the original Codex decision tree, and because the result would mean it’s a CCP and the site doesn’t think that’s right, they’ve ‘fudged’ the answers so that it doesn’t come out as a CCP. This clearly, would put them at risk of getting a non-conformance for this.

If you use the updated decision tree, it would go like this instead:

Question 1: ‘Is the hazard managed by the prerequisite programmes?’
Answer:– Yes, chilled storage is a control, under the prerequisite of ‘Storage and distribution’. Therefore it’s managed by a prerequisite and is not a CCP.

The other benefit of using the updated decision tree is that it means that only the really KEY hazards which are not managed by prerequisites continue on through the decision tree, making you focus on the KEY food safety controls.

Check your HACCP plan to see which decision tree you’re using and if you’re using the original version, make sure that you’ve not ‘fudged’ any of the answers to get the result you want.

When using the updated version of the decision tree it makes the prerequisites that you choose, really important, as this will determine which controls come out as CCPs.

To help you with this I’ve provided you with a list of the prerequisites that we use when carrying out a HACCP study for a site which has BRC Food Safety accreditation. You can use this in your HACCP plan and just add in your procedure references for each control/prerequisite. It’s also a useful way of working out if you have any gaps in your procedures.

To get your free copy of these, just click the button below.

In the next post I’m going through verification and validation and I have a great freebie for you – a metal detection validation fact sheet, look out for it!

If you found this post useful, check out our HACCP Documentation Packs below – they’ve been designed to take as much of the pain away from creating or updating your HACCP as possible!


  • Gail McMath says:

    Hi Kassy
    Following reading your Newsletter 17 about using the old codex decision tree, we had a look at the one we were using – the old one. As HACCP team leader, I thought it made sense to change to the new one. I then started looking through a Hazard Analysis for one of our plans and go through each of the hazards which we had previously deemed significant and apply the new decision tree questions. All were ok until we came to the metal detection step. My colleague, also a HACCP team member agreed.
    For Information:
    Process Step – Metal Detection
    Identified Hazard – Presence of metal in product
    Q1 Is the hazard managed by the prerequisite programmes ?
    We can answer yes to this as we have a metal Control Policy in place, knife checks, start up checks on machinery etc . If we go with this then control at this step is not a CCP.
    If we answer no to Q1 then its yes to Q2, yes to Q3 resulting in a CCP
    If we use the new tree then there is no CCP at this step. If we use the old there is.
    If we answer no to Q1 using the new tree could someone argue that we’ve ‘fudged’ the answer?
    Before we go any further I’m looking for some advice as you know auditors usually look at metal detection as a CCP. I’d rather get an NC for not answering the questions correctly than getting an NC if we remove the metal detection step as being a CCP.



    • Ruth Shaw says:

      Hi Gail,

      This is really important question, thanks for asking it – I’m sure it’ll help others too to know this.

      The list of prerequisites that we provided in this newsletter are aligned with the BRC topics, but you’ll notice foreign body detection is not listed. Foreign body detection is the topic in the BRC that covers metal detection.

      The reason it is not listed as a prerequisite is that prerequisites control site wide generic controls. For example knife control as you’ve said is a site wide generic control, as knives are used across the whole site, so knife control (or metal control or sharps control) is managed as a prerequisite – under Chemical & Physical Contamination Control.

      The control of metal detection is a control that is specific to a particular process step, it’s not a site wide generic control and therefore cannot be a prerequisite control. This is why metal detection control under foreign body detection is not listed as a prerequisite.

      Does that make sense?

      If you now put this through the decision tree again it should work fine for you and come out as a CCP.

      I hope that helps and thanks again for your question – keep them coming if you have any others!


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