Indirect drying will certainly reduce risks. Personally I'd only do some PAH testing initially to give you and your customers some confidence in the product you are drying. Depending on the outcome of the tests this will then guide you as to the frequency (if required) of further testing. Is PAH noted as an issue in dried seaweed? Do you customers require this test? If not then I'd possibly only test annually so if a customer asks you can have some results to show them and note that you do annual (or what ever frequency you decide) for monitoring purposes.
Thanks for a great suggestion!
Our consumers asked for PAH and dioxins, so I did more research and contacted lab to find out if we actually need to add these test to our routine testing regime.
Dioxin/PCB is for monitoring drying process (historically due to drying with coal burning dryers has long caused dioxin contamination).
Whereas PAH's are really formed in incomplete combustion, which is linked to the smoking process.
I think I will follow your suggestion and do some testing to identify levels and perform RA to find out the frequency of further testing.