Assessment of Milk Quality and Antibiotic Residues Detection in Milk Samples from Palestinian Market
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Date
2019-09-08
Authors
Hamdan, Dalal
Journal Title
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Publisher
An-Najah National University
Abstract
This study was conducted to evaluate the quality of milk in the Palestinian market during a period of 8 months, from June 2017 to January 2018. A total of 118 milk samples, of which 79 pasteurized, 14 raw and 25 (UHT) were collected randomly from the market, using the production date as the collection criteria. The samples were screened for antimicrobial residues using Delvotest SP-NT, and their osmolality was measured using Vapor Pressure Osmometer (VAPRO). In addition, the pasteurized and UHT milk samples were evaluated for physicochemical properties (fat, solids not fat; SNF; protein, lactose, ash, freezing point and pH), using (Ultrasonic Milk Analyzer) and pH meter. The results of the antibiotic screening test SP-NT showed that (36%) raw milk samples contained antibiotic residues above MRL. Meanwhile, the pasteurized milk samples (27%) were contaminated with antibiotic residues above MRL. None of 25 UHT milk samples were contaminated with antibiotic residue.
The average content of fat and solids in pasteurized milk samples was higher during winter (3.38%, 0.65%, respectively). The Freezing point and pH average were higher during summer (-0.5048°C, 6.78, respectively). Moreover, the average content of SNF, Protein and lactose were higher in autumn (8.04%, 2.96%, and 4.41%, respectively). The average content of (fat, SNF, ash, protein, lactose) and FP of pasteurized milk samples revealed non-significant differences (P>0.05) between seasons. Meanwhile, the average pH showed significant differences (P<0.05) between seasons.
The results showed that the average content of fat and protein in UHT milk samples were higher in spring (3.28%, 3.18%, respectively), the average content of solids and freezing point were higher in summer (0.65%, -0.5087°C, respectively). Moreover, the average of SNF and pH were higher in autumn (8.01%, 6.74, respectively). The Physiochemical properties average (fat, solids not fat; SNF; protein, lactose, ash, freezing point and pH) of UHT milk samples revealed non-significant differences (P>0.05) between seasons.
The osmolality average of raw milk samples, pasteurized and UHT was (309±37.86, 273±24.08, 271.76±7.46 mOsmol/kg, respectively). Moreover, the osmolality average of milk samples revealed significant differences (P<0.05) between raw and heat-treated milk samples.
The present study concluded that physiochemical properties and the osmolality of milk were affected by seasonal variation. Also, the study showed that the percentage of contaminant raw milk samples by antibiotic residue above MRLs is higher compared to that heat-treated milk samples.
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Assessment of Milk Quality and Antibiotic Residues Detection in Milk Samples from Palestinian Market