Hi Flotoyo,
You have posted in SQF Packaging Forum but are talking about Food.
Please clarify the kind of Product/Process you are involved with.
HACCP tends to assume a technical background (ie BCPA familiarity) is available. Do you have this already ?
HACCP utilises Risk Assessment. HACCP is still evolving. Risk assessment is by definition subjective = you can expect "experts" may not always agree.
There are many presentations available on "doing" a hazard analysis and determining CCPs, eg Codex, NACMCF, ISO. Which one are you attempting to implement ?.
Actually I suspect your difficulties have probably been experienced by most of the regular Posters here and many of us have had to choose a preferred "Way to Go" which is auditorially acceptable. However you will see many different but equally acceptable flavours of haccp utilised on this forum.
To illustrate yr problem, but not necessarily provide an instant solution, see these documents -
ccp1 - Unlocking Control Measures in Food Safety.pdf 409.58KB
115 downloads
ccp2 - Determining-control-measures in HACCP,Safefood.pdf 1.15MB
92 downloads
PS - as it happens, for traditional haccp, I have never, ever, used Decision Trees to determine a Process CCP. But Consultants usually prefer them for training since they are, at least in theory, easier to use/formalise for routine purposes.
I use Risk Matrices directly but this also IMEX necessitates some selectivity so as to achieve logically consistent results.
PPS - Hint - afaik, in traditional haccp, Decision Trees (except dedicated raw material ones) were/are intended to be applied to MANUFACTURING STEPS only. Hygiene related aspects are controlled by system-wide PRPs. (Some modern haccp treatments have expanded the use of PRPs to involve the Process also).
The newer Tree versions insert a Prerequisite query (= Not Significant Likelihood of Occurrence) at the beginning of Codex model chain.
P3S - the best haccp learning text I have found is "Practical Haccp" by Mortimore et al but no single volume is likely to answer all yr queries.