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Abstract
An approach to off-grid milk preservation for rural sub-Saharan African dairy farmers was developed. This approach branded as EvaKuula, involves a combination of two microbiostatic processes: thermization and evaporative cooling. The EvaKuula allows for extended storage of raw milk. Contrary to the chilling process, the EvaKuula process involves addition of heat to the milk (thermization) – followed by evaporative cooling. Although thermization is practiced in commercial dairies for extended storage of raw milk before processing, the application of thermization coupled with evaporative cooling for off-grid preservation of milk in the hands of smallholder farmers is an innovation.
In this research, we use computation fluid dynamics (CFD) to understand the mass, energy and momentum transfer between air and water during the evaporative cooling process in the context of milk preservation. We consider both the current design with a fan and a design with a static vent. CFD analysis was done using Ansys fluent code 19.2. We also measure the biochemical and microbial quality of milk to understand the degree of freshness of milk from the process. Milk biochemical parameters were measured with an ultrasound milk analyzer and microbial quality were analyzed following standard procedures.
The results for performance of the evaporative cooler with a modified vent were enough for milk preservation in terms of drop in air temperature (maximum 8.30C). The change in temperature is due to the exchange of mass and energy between air and water. The results for milk freshness showed that biochemical (fat at 4.25) and microbial quality (Total viable counts at 13000 cfu/ml), qualify evakuuled milk for grade one (top quality) fresh milk classification.
Potential impacts of these findings are; the results of milk freshness provide a science driven evidence in supports of inclusion of evakuuled milk in the raw milk quality standard. Additionally, results of the performance provide evidence for value engineering a new cost-effective prototype of the evaporative cooler with a static vent. Inclusion of Evakuuled milk in the standard may improve product confidence among sector players. This coupled with a potential of a low retail price can accelerate product diffusion among rural Sub-Saharan African farmers.
In this research, we use computation fluid dynamics (CFD) to understand the mass, energy and momentum transfer between air and water during the evaporative cooling process in the context of milk preservation. We consider both the current design with a fan and a design with a static vent. CFD analysis was done using Ansys fluent code 19.2. We also measure the biochemical and microbial quality of milk to understand the degree of freshness of milk from the process. Milk biochemical parameters were measured with an ultrasound milk analyzer and microbial quality were analyzed following standard procedures.
The results for performance of the evaporative cooler with a modified vent were enough for milk preservation in terms of drop in air temperature (maximum 8.30C). The change in temperature is due to the exchange of mass and energy between air and water. The results for milk freshness showed that biochemical (fat at 4.25) and microbial quality (Total viable counts at 13000 cfu/ml), qualify evakuuled milk for grade one (top quality) fresh milk classification.
Potential impacts of these findings are; the results of milk freshness provide a science driven evidence in supports of inclusion of evakuuled milk in the raw milk quality standard. Additionally, results of the performance provide evidence for value engineering a new cost-effective prototype of the evaporative cooler with a static vent. Inclusion of Evakuuled milk in the standard may improve product confidence among sector players. This coupled with a potential of a low retail price can accelerate product diffusion among rural Sub-Saharan African farmers.