Why is その used here?

Question

I found this definition of 食用{しょくよう}:

食べ物として用いること。また、その食べ物。「食用になる」

Which I read as

食｛た｝べ物{もの}として用｛もち｝いること。また、その食｛た｝べ物｛もの｝。「食用{しょくよう}になる」

Meaning

A thing that can be used as food. Also, that food. "To be edible"

I don't quite get what その could mean apart from that, but does that make sense here, as edible doesn't mean food, and according to jisho, 食用 means

for use as food; edible​

I am new to Japanese so forgive me if this is really obvious.

Answer 1

I believe you are misunderstanding the first part of the definition.

食べ物として用いること。

means

the use of something as a food.

The next bit specifies an alternate meaning that follows from a common use of the first meaning:

また、その食べ物。

Means

or, the food item [itself]

So 食用 refers to both the use of things as food and by extension food.

Thus,

食用 is either to make use of as food or something edible.

But to be edible is really 食用に適する

Answer 2

食用：
食べ物として用いること。また、その食べ物。「食用になる」

The definition means as follows.

(1) 食用｛しょくよう｝とは、食べ物として用いること。
(2) 食用｛しょくよう｝とは、(1)で「食べ物として用いること」と定義した時の「食べ物」。
用例{ようれい}：食用になる。