The recipe, descended from the medieval garlic sauces and a relative of the Roman moretum (a sauce made from coriander, rue, parsley and cheese crushed in a mortar and tied with olive oil), was born "officially" in 1863, codified by Giovanni Battista Ratto in "The Genoese cooker"
According to the Genoese pesto consortium, the ingredients used must be 7:
1) Genoese PDO basil (not less than 25%)
2) national extra virgin olive oil, possibly the Ligurian Riviera
3) Parmigiano Reggiano (with Grana Padano variant)
4) Pecorino Dop (Fiore Sardo)
5) pine nuts produced in the Mediterranean area, walnuts (optional, in place of pine nuts), obtained from "iuglans regia" of European origin
6) garlic of national production
7) salt produced in Italy.
According to the Genoese pesto consortium, the ingredients used must be 7:
1) Genoese PDO basil (not less than 25%)
2) national extra virgin olive oil, possibly the Ligurian Riviera
3) Parmigiano Reggiano (with Grana Padano variant)
4) Pecorino Dop (Fiore Sardo)
5) pine nuts produced in the Mediterranean area, walnuts (optional, in place of pine nuts), obtained from "iuglans regia" of European origin
6) garlic of national production
7) salt produced in Italy.