Isolation of Psychrotrophlc Bacteria
Raw milk samples obtained from the University
of Georgia dairy farm and pasteurized
milk samples obtained from commercial dairies
were incubated at 4"C for 5 d before analysis
by standard psychrotroph count (14). Isolated
colonies were streaked onto plates of standardreadings were converted to centipoise units
(CPS).
Water-holding capacity was estimated as
described by Parnell-Clunies et al. (13). Samples
(20 g) were centrifuged at 13,500 x g for
30 min at 10·C and the supernatant fluid
drained for 10 min. Water holding capacity was
expressed as the percentage pellet weight relative
to the original weight of the sample. After
pellets were weighed, they were freeze-dried
and reweighed. The index of protein hydration
(PHI) was determined as the grams of water
per gram of pellet solids (13)