On the meaning of "limited quantity" or "small scale", the debate is open and the shared definitions few. It is, in fact, a relative concept that depends on context (the case of a Mediterranean island is very different from the Amazon or from the Sahel, for example) and the type of production (growing onions is not like producing saffron or an aged Alpine cheese), and it is very difficult to give a certain number or precise formula.
In the case of the Ark of Taste (but also in other projects, like the Presidia and Earth Markets) we are interested in selecting products that could not be mass produced or industrial. In practice, "we are not able to calculate what is right, be we know very well how to recognize what is wrong" (Schumacher, 1973).
The products on the Ark are tied to a specific territory and the knowledge of a community, and it is precisely these two elements that define their limits. It is not possible to increase the quantity produced over a certain limit without fundamentally changing the nature of production.
If the volumes produced grow too much or too quickly (time is also an important variable), it increases the production area of the crops (which moves towards the model of monoculture), multiplies the number of animals being raised, intensifies the growing methods or leads to importing primary materials from outside of the production area (sometimes from very far away), and mechanises many if not all of the steps of the production chain, giving up craftsmanship at the risk of not obtaining the same quality.
The Ark of Taste is a catalogue of products, not producers. Therefore, it is not necessary to have an exact figure of the quantity produced (data which is, however, essential to have a Presidium), but it is important to at least identify an order of magnitude, to establish if we are dealing with an artisan or an industrial product.
To further understand this concept, you can read Small is Beautiful, published in 1973 by the economist and philosopher F. Schumacher.