I'd relate things as far as possible to what they understand. That's a lot to cover in 90 minutes so I'd either extend the session or be more realistic about what you can achieve in it. Do they really need to understand the 7 principles? If they do, I suggest spending at least 3-4 hours on them alone!
Anyway, as I was saying, I'd relate things to what they can understand and have experience with to illustrate your point. E.g. talk about preparing and cooking a chicken then using leftovers, as that can bring in all of the things you talk about and it's something probably everyone in the room will have done. I'd use lots of different media, use "spot the hazard" photographs in catering style environments, videos (even if not in the right language you don't have to play the soundtrack.) Get people giving you suggestions, make it interactive. Realise that many people learn in different ways, some people like to listen, some people like to see visual things, some like to experience things, make sure you have something in there for everyone and make sure you repeat things in lots of different ways, it helps understanding and memory.