I came across the sentence
on the English for Japanese speakers duolingo course. (I'm mainly doing it as dogfooding before suggesting it to a Japanese speaker learning English)
Is it normal in a context of talking about a foodstuff to use the katakana form?
Jisho.org doesn't indicate whether to use hiragana or katakana, and Wiktionary says
As with many terms that name organisms, this term is often spelled in katakana in biological contexts, as リンゴ.
Which I assume doesn't apply here. The Japanese edition of Wikipedia uses katakana, but it talks about it at least partially in a biological context.