Regulations for Food Labeling Article 12

Food with quality worse than the second grade of available national standard levels shall not be labeled, promoted or advertised with words of high or good quality which are easy to cause consumer confusion or misunderstanding.
中文原文 糧食標示辦法第12條
糧食品質規格有國家標準等級者,其品質規格未達國家標準二等以上時,不得使用優質、良質等容易引起消費者誤解或混淆之類似文字標示、宣傳或廣告。

English translation for reference only; the Chinese text prevails. Not legal advice.