文脈次第で。

It would depend on the overall context/style. In a marketing context "passionate about" could work. I also like "focusing on" as suggested.

Yes, this term is always a headache, as it truly depends on what "feels" right in the context. I like "meticulous about," but here are a few other ideas from my personal glossary:

(Be) dedicated to; (be) particular/selective/painstaking about; take great/exceptional care to (~verb); feel strongly about; (be) uncompromising on; insist on; have an uncompromising commitment to (quality, etc.); set great store by; spare no effort in (~(verb)ing).

Hope that helps!

やはり皆さんがおっしゃる通りに、文脈によっていろいろな表現を使うことになるので全てに対応する一つの英語はないかもしれません。

しかし、例文のような宣伝用途であれば、"insist on the highest quality", "insist on using only the freshest ingredients", "choose only the finest materials when.."のように、"insist on"の後に最上級の形容詞がつく表現が私のおすすめです。なぜなら、"be particular about..."はどちらかというとややネガティブな印象で企業よりも個人の癖に対して使われている表現だと私は思います。"Be fussy about.."はなおさら個人の癖を訴える表現ではないでしょうか。