Note: Many readers requested a blog about assessing milk quality at milk collection centers. This article does not replace a milk quality testing manual. However, if an organization would like to be trained, please contact us.
Handling milk production is different depending on the size of the dairy farms. Medium and large-scale dairy farms use milking machines to milk dairy cows. From each milking station, milk goes to a cooling tank and is stored at a low temperature. Then, a truck comes to the dairy farm to pump the milk from the cooling tank into the tank of the truck, which maintained milk at a temperature around 4⁰C. During the entire process from the farm to the milk processing factory, the cooling chain maintains milk at a low temperature to keep its quality.
At small-scale dairy farming, however, there are several challenges to maintain the quality of milk. One of the major challenges is the lack of a cooling system at the farm level. Usually, dairy farmers own a few lactating cows, often they have on average one to five cows. Even these dairy cows are local breeds with low yield, producing less than 5 liters a day each. Some farmers may own improved breeds. The low quantity of milk produced, in addition to the lack of investment capacity, explains the difficulty to invest in cooling system equipment. Furthermore, small-scale dairy farmers are not connected to electricity, which complicates the operation. The most efficient alternative is to establish milk collection centers within a radius near to dairy farmers.
Usually, farmers milk cows by hand and store milk into buckets or milk cans at room temperature, waiting for them to transport it to a milk collection center. The inability to cool the milk constitutes a tremendous challenge to smallholder dairy farmers. Thus, promoting milk production in developing countries requires an investment in a milk collection network system. As the milk collection centers receive milk from various farmers, it is crucial to ensure the quality of milk collected. Testing milk delivered by each farmer becomes a critical step at the milk center.
Running a milk collection center requires a few supplies and materials. Farmers or middlemen bring their milk to the milk collection center. The milk collection center agent assesses milk quality by testing milk from each bucket or can. There are various methods, but at least its acidity and density must be checked. The acidity checks the freshness of the milk and whether it can support heat treatment at the processing factory. The milk collection center runs the alcohol test to check the acidity. Usually, the ethanol concentration is between 60%-68%. If its acidity increases, milk turns sour and coagulates with alcohol. Milk is of good quality if there is no coagulation, clotting, or flaking. That is an indication that milk can support heat treatment, for instance, pasteurization, at the factory. The lack of a cooling system increases the risk of spoiling the milk. That the reason checking its quality is paramount at the milk center. Testing milk from each recipient or milk can also prevent contaminating the milk already stored in the cooling tank.
The second test is about checking any adulteration of the milk by measuring its density, which depends on its composition and temperature. This test requires a lactometer. At 20⁰C, the density of milk is between 1,026g/cm3 and 1.034 g/cm3. Milk density deviates from this normal range if water is added to the milk.
Improving milk quality from small-scale dairy farmers requires farmers’ education on raw milk handling and the establishment of milk collection centers equipped with cooling system and testing supplies as alcohol and lactometer. Using a pH meter might be the easiest method to assess the acidity of raw milk. However, supplying each milk collection center with pH meters might be expensive. The processing and the quality of the final dairy products depend on the quality of the raw milk. At least having these minimum tests allow a rapid assessment of raw milk delivered to the milk collection centers.