I make my own miso, so I haven’t bought any in years. I was surprised to learn that not all miso still has a live bacterial culture. Some of it has flavoring and additives. Last time I went to the supermarket I snapped some pictures of the ones that were still living and are additive free. As an aside, I didn’t see any that were one or the other.
What to look for:
生 (nama)- live (as in live culture)
無添加 (mutenka) – additive free
酵母が生きている (koubo ga ikiteiru) – the yeast is living
生詰 or 生詰め (namatzume) – “packed with life”, as in the culture is still alive
Note: the miso I make has three ingredients soy beans, rice malt and salt. Some misos will have barley as well.