Without plastics to seal in moisture, breads were much dryer than the loafs you get in the store today so they had a long shelf life. Pioneers had hardtacks, which also survived long ship voyages across the ocean and could last for years in a dry pantry. “Matzo bread is the unleavened bread from the Bible that sustained the Israelites across their travels and wanderings.”
In other games like the Stronghold series, bread was one of the longest shelf-life foods available, so why does it have to spoil so quickly in Farthest Frontier?