Many of the healthiest foods can be acquired tastes, and for newcomers to Japan, nattō is no different.
Full of fiber and probiotics, these fermented soybeans are a common Japanese breakfast food, but their neba-neba (sticky) texture and accompanying earthy musk can be a bridge too far for many who weren’t raised with it as a part of their diets.
While fresh air is usually the “enemy” of most fermentation processes, nattō was traditionally fermented in a vessel of breathable rice straw. This allows condensation and heat to escape the soybeans, allowing the aerobic bacteria within to breathe. Today, nattō is commonly available in supermarkets in single-serve containers; on close inspection, these packages, too, are dotted with pinprick holes that serve the same purpose.

AloJapan.com