How to store Genoese basil pesto
Absolutely in the fridge, both the one you make at home and ours. When the courier delivers your order, the jars will be packed in an insulated box with gel ice, to maintain the right temperature in the cold chain. Now, if the pesto is left out of the fridge for a few hours, nothing happens at a hygienic level; consider that it's like when you go shopping at the supermarket, so if a fresh product is at room temperature during the journey it's certainly not a tragedy... but then the jars must be kept in the fridge so as not to alter the organoleptic qualities. The unopened jar can be kept at a temperature of between 0°C and +4°C until the expiry date indicated on the label (if you have made it yourself at home, it is best to consume it within a few days).
When you want to cook your pasta with pesto, simply take the jar out of the fridge at the moment of serving and then season raw, avoiding using heat sources because it is a sauce that does not need to be cooked, at the most you can dilute the sauce with a little cooking water to make it creamier. If you have leftover pesto from the one you bought, just put a little oil to cover the surface to prevent it from getting airy and oxidising, then put the jar back in the fridge and use the rest within three days, which is the same home-made process we use here in Genoa.