Bring Grocery Bags If You Plan On Shopping In Loreto
I know this doesn't seem like a big deal, but you'll be thanking me when you're not trying to balance your groceries in your arms, spilling your salsa on the sidewalk outside the grocery store: Stores don't provide plastic grocery bags in Loreto; you'll need to bring your own bag if you want to use one.
They do offer the fancier reusable ones, but they cost about $1. Either buy one as a souvenir, or stuff a few old plastic or reusable grocery bags in your suitcase. While you are at it, stuff a couple trash bags too. Sometimes, the place where you are staying only provides one trash bag.