Churning in Raw Milk Samples and Its Effect on the Fat Test
Shipping or mailing milk samples, specifically
those of Dairy Herd Improvement
Associations, over long distances to centralized
laboratories has rekindled interest
in looking at the problem of churning.
Churning causes loss or unavailability of
fat in the fat determination. By simulating
and exaggerating transportation motion it
was shown that no churning was caused
when sample bottles were completely filled
or when the temperature was below 10 C,
even with partially filled containers. Churning
increased with time and with container
head space. Of several additives tested,
only sodium metaphosphate was effective
in reducing churning, but not completely.