Thanks for this.Sorry stupid question but does ISO17025 equate to UKAS accreditation?
Yes - UKAS is the UK body responsible for accrediting labs and testing services to the ISO17025 standard. If you use labs elsewhere in Europe outside the UK, you want to look for ISO17025 (in most cases, although there could be exceptions) rather than UKAS.
In terms of the process, my understanding is that for UK regulatory/852 Validation, a scoping of potential pathogens relevant to the products e.g. STEC, Listeria, needs to be done first, and then the end products are deliberately dosed with these pathogens so that the kill step e.g. baking can be confirmed as effective against relevant pathogens likely to affect end products.Is this understanding correct?
The regulation itself is pretty vague on actual requirements, but then it's intended to apply to a very wide range of businesses, from one-man coffee trucks to large multinationals. My experience has been that the regulators apply an expected amount of proportionality based on the nature of the business and activities, so if you're the one-man coffee truck then you're not going to be expected to have the same level of plan and associated verification/validation in place that you'd want to see in a high risk product made on a massive scale by a company that has (or should have) the knowledge and resource to implement a more comprehensive and robust HACCP plan. The regulation itself doesn't really go into any detail and indeed whilst Article 5(2)(f) gives a requirement to verify, the regulation itself doesn't actually mention validation.
It is worth noting that there are situations where validation based on appropriate (e.g. peer-reviewed journals, guidance from suitable industry bodies etc) literature can be acceptable, so you could also look at that. Bread isn't my area of expertise, but I would expect there to be quite a lot of published information on it.
Full challenge testing with intentional dosing is something I've only had to do once, and that was for a very unusual process/situation that I can't discuss due to NDAs etc. Nonetheless it's worth noting that this used surrogate organisms - known pathogens that are chosen for being hard to kill in your product matrix are a risk that most people don't want to intentionally introduce to their sites if they can avoid it