The pronouncement
of God's (Allah) name before eating
or drinking is with a twofold purpose. Firstly, as a recognition of
God's countless blessings upon us, and secondly as a supplication
for the continuation and abundance of these blessings in future. The
Prophet (pbuh) is reported to have stressed strict adherence to this
etiquette in a number of sayings ascribed to him. The
Prophet (pbuh) is reported to have said:

Whenever
anyone of you eats, he should say: '[I begin] with the name of God'.
If he forgets, he should then say: 'With the name of God, at the beginning
as well as at the end".