Various percentages (1.2% to 13%) of β-
cyclodextrin (β–CD) were added to water or
pasteurized whole milk to study β-CD crystallization
patterns. Influential factors such as
crystallization time (4 to 12 h), crystallization
temperature (45º vs. 72ºF), and centrifugation
speed (25 to 3000 × g) were investigated. Optimized
crystallization conditions were verified
in antibiotic-tainted raw milk samples via
the enzyme-linked receptor-binding assay and
by solids partitioning. In water, β-CD precipitate
increased significantly as β-CD concentration
and crystallization time increased, but
was independent of the centrifugation speed.
In pasteurized whole milk, precipitate increased
as β-CD concentration, crystallization
time, and centrifugation speed increased. The
best β-CD precipitation conditions in milk
were designated as: 9.1% β-CD concentration
(w/w), 4 hour crystallization time, 45ºF, and
centrifugation at 25 × g for 10 minutes.
Eleven cows were treated with cephapirin sodium
or cephapirin benzathine. Milk was obtained
12 h later and treated with β-CD. As β-
CD concentrations increased, precipitates increased,
and the corresponding supernatants
showed reduced concentrations of antibiotics
when tested by enzyme-linked receptorbinding
assay. Results indicated that β-CD
may have the potential to reduce the residues
of cephapirin sodium or cephapirin benzathine
in antibiotic-tainted raw milk.
