Hygienic and compositional quality of Raw Milk Produced by Smallholder dairy farmers in Lusaka Province of Zambia
This study was carried out to evaluate the hygienic and compositional quality of raw milk produced by smallholder dairy farmers (SHDFs) in Lusaka province of Zambia. It was conducted during the months of January and February 2014. The hygienic and compositional quality of raw milk was determined by assessing its Somatic Cell Count (SCC), Total Bacteria Count (TBC), Total Coliforms Count (TCC), Antibiotic Residues (ARs), added water and milk components. Altogether, 83 samples of raw milk were collected and analyzed at the University of Zambia, School of Veterinary Medicine Public Health Laboratory. Somatic Cell Count (SCC) of milk was measured using a DeLaval Cell Counter (DeLaval International AB, Sweden). Total Bacteria Count (TBC) and TCC were determined by culturing the samples of raw milk on Standard Plate Count Agar (SPC) and Violet Red Bile Glucose Agar (VRB) respectively, followed by colony counting after 48 hours of incubation at 32°C. Milk composition and added water were determined using a LactiCheck Ultrasonic Milk Analyzer (Page & Pedersen International Ltd, USA) while testing for presence of ARs was done using the Copan Milk Test 100 (Copan Diagnostics Inc., Denmark). On composition, it was found that Butter Fat (BF) for raw milk from 23 out of 83 farms (27.7%) was below recommended standards and minimum legal limit of 3.2% fat. Solid Not Fat (SNF) for raw milk from 26 out of 83 farms (31.3%) was below recommended standards and minimum legal limit of 8.3%. Density for raw milk from 28 out of 83 farms (33.7%) was below recommended standards of 1.028 g/cm3. On adulteration of milk with water, it was found that 26 out of 83 farmers (31.3%) had added some quantity of water varying from 9.46 – 34.3 % to their raw milk. It is worth to mention that all samples which were found to be adulterated with water had low density, low BF and low SNF content. It was therefore concluded that water adulteration was the probable cause of low density, low BF and low SNF in milk. Total Bacteria Count (TBC) ranged from 445 to 2.6 x 106 cfu/ml of raw milk. Milk from 5 out of 83 farms (6.02%) had TBC above the recommended standards and maximum legal required limit of 200,000 cfu/ml of raw milk. Total Coliforms Count (TCC) ranged from 100 to 100,000 cfu/ml of raw milk. Milk from 4 out of 83 farmers (4.82%) had TCC above the maximum recommended limit of 50,000 cfu/ml of raw milk. The study concluded that sanitary quality of milk produced by smallholder dairy farmers in Lusaka province of Zambia, as far as bacterial contamination was concerned in totality was within acceptable standards opposite to the findings in many other countries in the region. This might be attributed to the fact that recently there has been a lot of emphasis and support towards clean hygienic production of milk and good price paid by milk processing companies for raw milk which has low bacteria content. On SCC, milk from 51 out of 83 farmers (61.45%) did not conform to recommended standards. It had somatic cells more than the maximum recommended number of 300,000 cells / ml of raw milk. Somatic Cell Count (SCC) ranged from 263 to 22.3 x 106 cells/ml of raw milk. This was due to subclinical mastitis not noticeable on clinical observation. Raw milk from 25 out of 83 farms (30.1%), tested positive for ARs while the other 58 farms (69.90%) were found negative for ARs. This study has produced the first ever report on ARs in milk in Zambia. A higher percentage of ARs in raw milk was found in the study than what has been reported in many other countries in the region. The high SCC, ARs and added water found in the milk is a matter of serious concern. It indicates that there is need for further education and training of the farmers in aspects of good milk production which should include correct usage of antibiotics and observance of withdrawal period after antibiotic treatment. There is also need to extend this study to wider locations of milk producing areas in Zambia.
Dairying , Milk Processing-Lusaka, Zambia