Dairy production in periurban area of Niamey: milk quality and microbial contamination

Abstract

In developing countries, dairy products play a very important role in food security. In Africa, many problems have hindered local milk production, making dried milk imports from Western countries necessary. Milk production should be improved to allow these countries to unburden themselves from their economic ties and to reduce health problems related to the use of dried milk (FAO 2000). A development project to improve the milk chain quality in Niamey is carried out through the installation of a dairy (Cooperative Laitiere de Niamey-CLN) collecting milk from farmers of the periurban area, requiring high quality milk and guaranteeing a daily income to the 23 farmers. Milk quality is influenced significantly by stocking and transport methods: a temperature higher than 20°C encourages the growth of lactic acid bacteria, causing the acidification of milk (pH≤6.5; Table 1) and the proliferation of pathogenic bacteria (Staphylococcus aureus, Salmonella spp., Listeria monocytogenes, Escherichia coli and Clostridia) (Mellenberger and Kirk 2001). The pH in relation to temperature is one of the control parameters during milk transformation, both as quality index and as good conservation indicator (Corradini 1995). The high environmental temperature and the use of unsuited containers cause risks of microbial contamination of the milk. The aim of this survey is to evaluate microbial contamination at time of milking and its evolution during transport, until its conservation before transformation.