Papers describing food drying techniques normally list the obvious contamination risks of drying in the open air as a major disadvantage and and based on this dismiss its application. However, the large volumes of food that are sun dried every year and the savings in energy and capital bely this quickly reached conclusion.
Searching the literature and regulations doesn’t give any guidance on the advisability of establishing a new sun drying business.
However, the two videos below show the large scale use of sun drying and the associated technologies applied at Cecilia’s Farm, near Prince Alfred in South Africa.
It seems that the critical point about the sun dried business they run, is that all fruit is washed before further processing and or packaging. Arguably this makes it comparable to fruit which is often not peeled, packaged salad and leafy vegetables. These are grown in the same environment and simply washed before eating.
The massive advantage of sun and to a lesser extent solar drying is that they produce shelf stable foods with minimal environmental impact and low processing and packaging costs.