I think that the value chain of slow food doesn't differ very much from the value chains of other enterprises only because it is non-profit. I would suggest that the primary activities like marketing and sales are also important for slow food to establish in the market and make their mark so that buyers get to know this movement. I think that this is also achieved by creating a company logo.
The support activities like administration or technology development also fits to slow food, because machinery in agriculture needs to be maintained and business operations with partners need to be regulated.
Greetings