That the word 'food' denotes the earth is to be inferred from the fact
that the section in which the word occurs has for its subject-matter the
creation of the elements; as everything eatable is a product of the
earth, the term denoting the effect is there applied to denote the cause.
In the same chapter, where the colour of the elements is mentioned ('The
red colour of a flame is the colour of fire, the white one that of water,
the black one that of food '), the collocation of words clearly shows
that 'food' means something of the same kind as fire and water, viz. the
elements of earth. And there are other texts also which treat of the
same topic and declare the origination of earth from water, cp. Taitt.
Up. II, 1, 'from fire sprang water, from water earth.' All this proves
that the term 'food' denotes earth, and that hence earth originates from
water.
Fire and the other substances, the origination of which has been
detailed, are mentioned merely as instances, and it must be understood
that also other entities, such as the 'Mahat,' and so on, originate only
from the immediately preceding cause, in agreement with scriptural
statements. And texts such as 'From him is born breath, mind, and all
organs of sense, ether, air, light, water, and the earth, the support of
all' (Mu. Up. II, 1, 3); 'From him is born that Brahman, name, form, and
food' (Mu. Up. I, 1, 9); 'From that Self there sprang ether' (Taitt. Up.
II, 1, 1); 'It (i.e. that which is) sent forth fire' (Ch. Up. VI, 2, 3)--
(which seems to teach the direct origination from Brahman of the
different elements, and so on)--may be interpreted on the understanding
of Brahman being their mediate cause also.--This primâ facie view the
next Sûtra disposes of.