general merchandise totaling more than 5400 yen, tax included
消耗品と一般それぞれ = consumable goods and general merchandise
税込 = with tax / including tax
以上 = above -> exceeding
じゃない = not
と = if
できません = can't
免税 = duty free -> tax exempt
Purchases of consumable goods exceeding 5400 yen including tax are eligible for tax exemption.
または
Purchases of consumable goods under 5400 yen (including tax) are ineligible for tax exemption.
「Tax exempt」は形容詞として使って、「tax exemption」は名詞として使っています。動詞なら、「be」、「be eligible for」や「qualify as」を使えます。
This qualifies as tax exempt.
This is tax exempt.
This is eligible for tax exemption.