"It is pork."
Translation:C'est du porc.
What's this meat? It is (some) pork
Quelle est cette viande ? C'est du porc = "some pork" as "an undefined quantity of a non countable thing".
In that case where you could add "some" without changing the meaning of the sentence, you have to translate to the French partitive articles: du (contraction of preposition "de" + definite article "le") or de la (in front of a feminine noun).