All praise goes to the almighty God, the creator and supreme authority of the universe, who empowered the author to successfully complete the research work. The author is deeply grateful to Professor Akter Uz Zaman, Head of the Department of Dairying and Poultry, Chittagong University of Veterinary and Animal Sciences, for his constant help and valuable advice during the research work. The most alarming fact was that two of the NBPRM samples from Chalkbazar area contained formalin.
Being the second largest metropolitan and commercial capital of the country, the entrepreneur from Chittagong has established many dairy farms. There is a huge demand for liquid milk in the city, hence the city's milk producers enjoy a high price of around Tk 38-40/litre. In Chittagong there is no such co-operative system of milk marketing as in the northern part of the country.
A large part of the milk is delivered to the nearby sweetmeat shops and restaurants, while a significant part goes to retail stores and suppliers for household consumption. Most of the household stores also follow this method to supply fresh milk to the monthly customers. There is always a chance of adding preservatives with the raw milk by the middlemen/baperies to keep the shelf life of the milk longer.
This study was conducted with an aim to find out the physical and chemical properties of farm produced liquid milk and unbranded packaged raw milk so that the effect of marketing system can be found out in Chittagong metropolitan areas.
Review Of literature
- Constituents of Milk
- Nutritive Value of Milk
- Physical Parameters of Milk
- Chemical parameters
- Adulteration and Preservative of Milk
Milk proteins are not a single compound, but include three main proteins, namely casein (80% of total protein) and lactalbumin (18%) and lactoglobulin (2%). Water makes up the largest part of milk and ranges from 80 to 90%, depending on the species and breed. Water serves as a carrier for all milk components. 2009) found in their study that the specific gravity of milk from different sources from the Chittagong metropolitan area ranged from 1.025 to 1.028, with the lowest value for the vendor-supplied rural milk. 2007) demonstrated in a comparative study that the specific weight of milk does not differ significantly in different months of the year.
1984) reported that the specific gravity of milk obtained from BAU Dairy Farm and the local market were 1.031 and 1.026 respectively. Since the higher the milk fat content, the lower the specific gravity will be. 2009) showed in his experimental study that the butterfat of milk from different sources from Chittagong metropolitan area ranged from 3.52 to 4.01 and the rural milk supplied by the vendor had the highest value of it. Rahman (1995) observed that the mean fat percentage of milk samples collected from Baghabarighat dairy was 4.28±0.028.
Rahman (1995) observed that the average SNF content of milk collected from Pasteurization Plant and Baghabarighat Dairy Plant was 7.96% respectively. 1984) also reported that lower SNF% in local market milk than the milk from BAU Dairy Farm, Mymensingh. Campbell and Marshall (1961) stated that milk adulteration is often toxic to human health. 2009) conducted a study to discover the preservative used in different sources of milk in Chittagong metropolitan area.
Materials and Methods
Collection of Sample
- Number of Samples
- Procedure of sampling
Agarwala and Sharma (1961) stated that addition of water, skimming and watering reduced this fat. They reported that adding water not only dilutes the milk, but also carries the risk of introducing germs from contaminated water. Fluid milk samples were collected directly from selected farms in different areas of Chittagong city. Morning and afternoon milk were collected separately from each farm after milking.
In case the seller supplied unbranded milk, the samples were collected from retail stores, cold corners and departmental stores in the selected area; from which farm milk samples were previously collected.
Methods followed for milk testing
Results and Discussion
- Physical and Chemical Quality Assessment
- Specific Gravity
- Fat Content
- Solids -Not -Fat Content (SNF)
- Total Solids (TS)
- Water Content
- Acidity
- Qualitative variation of Morning and afternoon Milk
- Adulteration
- Commercial life
This may be due to differences in breed and feeding problems with the cows. The fat percentage of NBPRM was satisfactory, and statistically there is no significant difference between FPFM and NBPRM, but lower SNF content (Table 2) indicates that afternoon milk was generally used for packing raw milk, since afternoon milk contains much higher fat than morning milk (table 2) 3). The SNF percentage of FPFM corresponded to the parameter of UPHA (1965) and the results of Itzerot (1960).
Most of the NBPRM samples did not meet the percentage of SNF according to the PFA Rules (1986). But the result was roughly similar to the experimental findings of Rahman (1995). The SNF percentage of NBPRM was significantly lower than FPFM. In the case of NBPRM the percentage of fat is not like the results of Rahman (1995), so from the above consideration the low percentage of SNF may be the result of adulteration of milk with water.
The TS% of most FPFM samples was satisfactory, which is similar to the results of Yadav and Sarwat (1982) and Islam et al (1984) where they found lower total solids in milk from local markets (8. 5-12%). A higher water content of the non-branded milks on the market indicates that they have been adulterated with water. The result of high water content in market milk is in agreement with the results of Islam et al. 1984), who found higher water content in milk (89.9% collected from local markets in Mymensingh Town).
High acid content in most FPFM and NBPRM indicates unhygienic milking conditions and unsatisfactory shelf life of the milk. Statistically significant variation was found between the quality of FPFM in collected morning and afternoon samples. There is no statistical variation found in terms of density and SNF% of the morning and afternoon milk, which describes the reason for higher fat percentage in afternoon milk.
Among them, 4 out of 6 samples in Khulshi, 2 out of 3 in Bakalia, 2 out of 4 in Biozid, 3 out of 4 in Chandgaon and 4 out of 7 samples in Chalkbazar were found to be impurity with water (specific gravity less than 1.026). Since FPFM was collected directly from the farm, no adulteration test was performed on these samples. Since FPFM was collected directly from the farm, no preservative test was performed in these samples.
Out of the 27 NBPRM samples tested within 4 hours of collection, 10 samples were positive in APT (Alcohol Precipitation Test).
Summary and Conclusion
- Addition of the sulfuric acid into the butyrometer
- Mixing of sample
- Measurement of the Sample
- Addition of amyl alcohol
- Insertion of stopper
- Mixing of the contents
- Centrifuging
- Temperature adjustment
- Reading of percentage of fat
- Checking of the reading
- Cane sugar Detection
- Starch Detection
- Milk powder Detection
- Formalin Detection
- Hydrogen peroxide detection
- Bicarbonate detection
Elaborate on the assessment of the chemical quality of milk from primary cooperatives (Milk Vita). Determination of fat in milk: The fat percentage of the milk sample was determined using the Gerber Fat Test Method. The mixture is then centrifuged in a special type of Gerber tube. The volume of fat secreted is then read on the graduated portion of the butyrometer tube at a fixed temperature.
Using the automatic measure, 10 ml of sulfuric acid was measured in the butyrometer. Care is taken not to wet the neck of the butyrometer with acid. During the delivery of milk, the pipette was held by current in the neck of the butyrometer.
Then the tip was caressed so that the jet against the base of the neck of the butyrometer kept from being wet. 1 ml of the amyl alcohol was measured into the butyrometer by means of the standard alcohol pipette. The neck of the butyrometer was wet with alcohol. The butyrometer was placed in a protected stand until the contents were thoroughly mixed and after this no white particles could be seen.
The water level was maintained above the top of the fat column in the butyrometer. Before a measurement was taken, the position of the fat columns was adjusted to bring the lower end of the fat column onto a main marker. The scale readings were recorded accordingly at the lowest point of the far meniscus and at the dividing surface of the fat column. fat and acid; the difference between the two measurements indicates the weight percentage of fat in the milk. When the measurement was made, the butyrometer with the graduated protein was held vertically and the reading point was kept level with the eye.
The butyrometer was returned to the water bath for a further 3 minutes and then a control fat percentage reading was taken as soon as possible after removal from the bath. Then 1 ml of HCL and 0.1 g of resorcinol were added to the test tube.
