Q. If I use a fleishig spoon to juice a lemon is the lemon fleshig?

A. Most Poskim agree that lemons are considered a dovor chorif or foods with a sharp taste. (Shulchan Aruch Y.D. 96: 4 et. al.) However, Shach (96: 20) mentions that lemons are not as sharp as other produce such as radishes.
Horav Shlomo Miller’s Shlit’a opinion is that if pressure was used to extract the juice out of the lemon using as expected, the edge of the spoon, it is reasonable to treat the spoon as a dull knife, and the lemon would in this case absorb from the spoon and may become fleishig.

Rabbi A. Bartfeld as revised by Horav Shlomo Miller Shlit”a