Informations et ressources scientifiques
sur le développement des zones arides et semi-arides

Titre : Bridging the gap : improving milk quality on smallholder dairy systems in Kenya

Auteur : Nyokabi, Simon Ndungu

Université de soutenance : Wageningen University

Grade : Doctor 2023

Résumé partiel
Milk and dairy products play an important role in diets globally, providing a rich source of vitamins, proteins and essential minerals. Dairy production constitutes an important livelihood source in Kenya, however, milk quality is poor and constrains milk processors, while placing consumers at risk. This PhD thesis explores the current state of milk quality and safety in Kenya, and factors that influence the quality of milk produced in smallholder dairy farms and traded in dairy value chains (DVCs), to identify improvement strategies.

In Chapter 2, I employed a farming systems approach to explore milk composition, microbial contamination and adulteration in Laikipia, Nakuru and Nyandarua counties. I stratified smallholder dairy farming systems into intensive farming systems in urban locations (UL), semi-intensive farming systems in mid-rural locations (MRL) and extensive dairy farming systems in extreme-rural locations (ERL) based on market quality (i.e., access to input and output markets) and access to production resources (i.e., labour and land). Milk samples were collected at informal and informal value chain nodes - farms, informal collection centres, informal retailing centres including milk vending machines, and formal bulking centres - and analysed for physicochemical composition, microbial contamination and adulteration. There was no difference in raw milk quality between farming systems locations or between value chain nodes. Milk quality was compared to Kenya Bureau of Standards (KeBS) standards, with physicochemical composition (means and standard error) found to be within standards. The protein percentage was below KeBS standards at all value chain nodes, except at formal bulking. There was significant contamination of milk samples : 16.7% of samples had added water, 8.8% had somatic cell count SCC above 300,000, 42.4% had E. coli, 47.9% had Pseudomonas spp., 3.3% had Staphylococcus spp. and 2.9% tested positive for brucellosis antibodies. Unhygienic milk handling and storage practices were observed at farms and all value chains nodes, resulting in high levels of milk microbial contamination which could pose a public health risk to consumers and constrain milk processing.

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