This topic needs to be clarified.
What defines a traditional food preparation/process? I suggest that we consider processes that modify a major component of the diet, so storage of a grain would not but fermentation would, constitute a traditional food preparation.
Another question to focus the discussion is a definition of at what stage does a process cease to be traditional: since Pasteur canning has been a traditional presservation/preparation process, it is now a traditional practise that is still applied today at the industrial scale. As such it does not need special measures to preserve the knowledge.
Do we expanded the topic to include 'traditional' methods of preserving foods since food preservation is a critical part of achieving food security.
Do we consider preparations/process that influence the toxicological profile of a food? There are processes that either remove toxins from the ingredient - (rendering them a safe source of nutrition) or increase the contamination (particularly in the case of the mycotoxins).
Links and resources:
Indigenous Peoples’ food systems: the many dimensions of culture, diversity and environment for nutrition and health
Comparative Assessment of Indigenous Methods of Sweet Potato Preservation among Smallholder FArmers: Case of Grass, Ash and Soil based Apporoaches in Zimbabwe
FSN Forum discussion: Looking back to effective rural practices ... Did we miss something?