Thks for the picture.
I anticipate yr query is related to differentiating CCPs/OPRPs for iso22000 or fssc22000.
I deduce the tree is intended to respond to clause 7.4.4 (a-g) in iso22000 standard
I agree with GMO that the tree is not very satisfactory although it does cover several/most parts of clause 7.4.4(a-g). IMO there are better iso22000-trees previously posted here..
Yr query (I assume it is ISO-oriented) is IMO a complicated one to answer. i have attempted below.
Synergy is the interaction of two or more Hurdles or Microbiocidal Steps so that their combined effect is greater than the sum of their individual effects.
Regarding the occurrence of combination control measures (CMs) you can find iso-decision trees having at least 3 (maybe more) different approaches to determine whether a combination CM is a CCP or OPRP, all methods seem to be acceptable to auditors –
(a) a single CM which achieves control is regarded as favouring a CCP while a combination CM which achieves the same control (ie “works”) is regarded as “favoring” a OPRP. Such trees may ignore mention of synergy.
(b) a single CM whch achieves control is regarded as no different to a combination CM, ie either may ultimately be a CCP or OPRP depending on the other ISO-criteria. Such trees may ignore mention of synergy.
(c) a single CM which achieves control is regarded as “favoring” a CCP while a combination CM is regarded as favoring a OPRP but only IF the combination CM “involves” Synergy. Such trees will probably mention Synergy. ((c) is a restricted version of (a))
(d) a 4th possibility which I think can occur in practice (see link below) could be where a single CM might “work” but a combined CM works “better” due to synergy. Afaik there are so far no specific iso-decision trees for such a scenario.
Your tree appears to be similar to type (c) above.
It is also possible to find some iso-analyses which consider the occurrence of Synergy favors a CCP (!) but I think these are in the minority.
Welcome to the world of ISO-HACCP !
I can probably direct you to published examples of all the above if you need.
If you would like to see a brief illustration of “synergy” (sort of type (d) above) can try the attachment/link in this post –
PS - if the query was not iso-oriented, you will need to clarify further.