TY  - JOUR
T1  - Application of Osmometry in Evaluating Effects of Antimicrobial Agents on Milk
Fermentation
AU - Musara, Colin AU - Pote, William 
JO  - Research Journal of Dairy Sciences
VL  - 8
IS  - 3
SP  - 22
EP  - 26
PY  - 2014
DA  - 2001/08/19
SN  - 1993-5277
DO  - rjdsci.2014.22.26
UR  - https://makhillpublications.co/view-article.php?doi=rjdsci.2014.22.26
KW  - Milk
KW  -fermentation
KW  -antimicrobial agents
KW  -osmolarity
KW  -osmometry
AB  - Antimicrobial agents for treatment of mastitis
in dairy cows may result in drug residues in milk,
suppressing production of fermented dairy products.
Since, lactic acid from fermentation normally raises milk
osmolarity, the objective of this study was to assess the
validity of osmometry in evaluating effects of
antimicrobial agents on milk fermentation. The 10 test
tubes each containing ultra high temperature treated
milk+starter culture (Lactococcus lactis sp. lactis) were
prepared. Using serial double dilution, cloxacillin
benzathine (dry cow) was added to 5 test tubes at
75-1200 mg L<sup>&#150;1</sup>and erythromycin and trimethoprim
(lactating cow) to the remaining 5 test tubes at
62.5-1000 mg L<sup>&#150;1</sup>. A negative control with neither starter
culture nor antimicrobial agent and a positive control with
starter culture but no antimicrobial agent was included.
All samples were incubated at 30&#176;C for 2 days and
osmolarity monitored by a cryoscopic osmometer. From
a starting value of 301&#146;1.72 mOsmol L<sup>&#150;1</sup>(mean&#146;SD),
maximum osmolarity values after 2 days were 315&#146;7.07
for non-inoculated antimicrobial-free milk, 463&#146;19.91 for
inoculated antimicrobial-free milk, 328&#146;9.07 for
inoculated milk containing erythromycin and
trimethoprim and 507&#146;35.53 for inoculated milk
containing cloxacillin benzathine (n = 6). Results from
negative and positive controls were consistent with
absence and presence of normal fermentation,
respectively. Erythromycin and trimethoprim significantly
(p&#60;0.05) inhibited fermentation at all concentrations
throughout the incubation period. Cloxacillin benzathine
exhibited significant inhibition at higher concentrations on
day 1 of incubation but none on day 2.
ER  -