I remember one conlang relay I did was a recipe. Most of the ingredients translated, but Daryn wasn't a big flour-using culture, so I had to just say 'ground grains'*. I just used onion as a loanword. (Bread is in my dictionary as a loanword, too.) The other time it came up, the passage had already been in Klingon, and I decided it was safe enough to just insert a local highly-intoxicating beverage in place of the Klingon word for 'local highly-intoxicating beverage', since whatever information that had been gained by specifying was gone.

* Even then, I don't know how taxonomically accurate 'grain' is as a classification, and ignoring things like acorns, which can also make flour.