The night's milk and the morning's milk should never be mixed before
starting for the factory, but kept in separate cans and so delivered.
The effect of mixing will be seen soon enough at the factory, and
often much too soon in hot weather. If the morning's milk were made
as cool as the night's, the effect of mixing would not be so speedy
and disastrous. But it appears to be an immutable law, that reducing
the temperature and then raising it hastens decomposition. A low
temperature only retards decomposition; it does not prevent it, unless
very low and it is continued. As soon as the temperature is raised,
decomposition sets in with accelerated rapidity, as if to make up for
lost time. Hence, we have always looked upon low temperatures in the
dairy as objectionable. As low as 60 degrees but not below 50 degrees
is the limit which we prefer. We think this range more effective
for long keeping than a lower one. Certainly, dairy goods made and
kept within this range will not go to decay so soon as in a higher
temperature.