This pertains to "What is the difference between tempeh and natto?"

In that article, the author states that tempeh is soy mixed with a cereal grain and that it is inoculated with "beneficial bacteria," and that natto is not inoculated with anything.

Tempeh is not restricted to soy, and it's typically not mixed with anything. Furthermore, the soybeans used to make it are inoculated with the mold (as in, fungus) Rhizopus oligosporus.

Natto is inoculated with the bacterium Bacillus natto, creating an overwhelming garbage-like scent and a sliminess characteristic of Bacillus species. The source of this error may be that for natto, soybeans are traditionally steamed and wrapped in rice straw, then left to ferment; this works, howe'ver, because B. natto is naturally present on the straw.