Source: F. Blass and A. Debrunner, A Greek Grammar of the New Testament and Other Early Christian Literature (trans. Robert W. Funk; Cambridge: Cambridge University Press, 1961), §101
Here are the instances of τρωγω in the Epistle of Barnabas and the Shepherd of Hermas, referenced above:
"And do ye all spit on it, and goad it, and bind the
scarlet wool about its head, and so let it be cast into the desert." And
when it is so done, he who takes the goat into the wilderness drives it forth,
and takes away the wool, and puts it upon a shrub which is called Rachél, of
which we are accustomed to eat (τρωγω) the
shoots when we find them in the country: thus of Rachél alone is the fruit
sweet. (Barnabas 7:8)
Moreover he says to them in Deuteronomy, "And I will
make a covenant of my ordinances with this people." So then the ordinance
of God is not abstinence from eating (τρωγω), but Moses spoke in the spirit. He mentioned the swine
for this reason: you shall not consort, he means, with men who are like swine,
that is to say, when they have plenty they forget the Lord, but when they are
in want they recognise the Lord, just as the swine when it eats (τρωγω) does not know its master, but when it
is hungry it cries out, and after receiving food is again silent. (Barnabas
10:2-3)
And you shall do thus: After completing what has been
written, in that day on which you fast you shall taste nothing except bread and
water, and you shall reckon the price of the expense for that day which you are
going to keep, of the foods which you would have eaten (τρωγω), and you shall give it to a widow or
an orphan or to some one destitute, and you shall thus be humble-minded that
through your humility he who receives it may fill his soul and pray to the Lord
for you. (Herm Sim 5.3.7)