Wow! I'm trying to understand what I'm being told here.
Are you saying that perishable food should not be eaten after 4 hours at room temperature? Is that right? How do you make and decorate a cake in 4 hours, let alone allow clients enough time to have them on show, say for a reception, before eating? And what about commercial cakes on sale in supermarkets that aren't refrigerated but have days on their use-by dates?
I clearly have a lot to learn, and will do some research into this, but have I understood you correctly?
Hi Bramsley! It is great that you are willing to learn more about this topic, to keep your family/clients safe!
Since you are in the UK, here is a link that might be of help to you: http://multimedia.food.gov.uk/multimedia/pdfs/publication/hygieneguidebooklet.pdf
It seems to contain similar information to our US ServSafe classes, which are required of at least one staff member or owner of every restaurant here (at least in my state). The potentially hazardous nature of food depends on many things, including pH, water activity, acidity and nutrient content, along with how it was processed (cooked/fresh/etc.) So in your original example, I would have felt safe using the commercial preserves in a cake that would be held at room temperature, but I still would only consider a couple of days the maximum total time from beginning to end, if I weren't able to fridge or freeze it. Your problem was when you added fresh raspberries to the mix - they are a perishable item. Fresh fruit is perishable. The berries in the commercial preserves not only were processed (cooked, which helps kill some organisms) they also are being helped along by the sugar and acid in the preserves.
The cakes in grocery stores probably contain sleeve fillings, which can be shelf stable. They are commercially manufactured just for that purpose.
As much as customers want to have it all (highly detailed/decorated cakes with all the best, fresh fillings) sometimes you just can't accommodate what they desire, unless you can do your decorating inside of a walk in cooler. :)
Please ask if you have any more questions!