This ingredient can be bought at the Deli Cioso stores that are located in the different cities of Paldea.
You will need to earn at least one Gym Badge to unlock bacon as an ingredient in the Deli Cioso. Once you meet this requirement, the ingredient will be added to the store list. And from there, you can browse the menu and buy Bacon for 150 Pokédollars.
You can find Deli Cioso points of sale in the following locations:
mesagoza
Montenevera
Porto Marinade
cortondo
Levincia
artazon
cascarrafa
medallion
To find the location of the Deli Cioso store, you will have to access the in-game map, zoom in once you are in any of the following cities and hover over the different icons. This way you will be able to see the names of all stores and points of interest, including Deli Cioso.
This is all you need to know about how to get bacon in Pokémon Scarlet Violet per possible so you can find this ingredient quickly.