MILK POSTHARVEST LOSSES, QUALITY AND SAFETY AND THEIR EFFECTS ON HOUSEHOLD INCOME AND PER CAPITA MILK CONSUMPTION ALONG THE DAIRY VALUE CHAIN IN CENTRAL HIGHLANDS OF ETHIOPIA

Abstract

The study was conducted in Selale-Addis, Ambo-Woliso, and Adama-Asela milk sheds in Ethiopia with the objective to investigate milk postharvest losses, their causes, mitigation strategies, physicochemical, compositional, microbial quality, and safety of raw milk, and their effects on household income and per capita milk consumption in the study area. The three milk sheds were purposively selected based on their potential for milk production, whereas households were selected randomly and proportional to the number of farmers owning at least two milking cows. A total of 296 smallholder dairy producers, 16 milk collectors, 3 milk processors, 35 milk retailers, and 115 milk consumers were selected and interviewed using a semi-structured questionnaire separately prepared for each actor. Milk samples were collected from 54 smallholder dairy producers, 9 milk collectors, 27 milk retailers, and 27 milk consumers. The physicochemical and microbial quality and safety of raw milk samples were analyzed following standard procedures. Data for milk postharvest loss were analyzed using Statistical Package for Social Sciences (SPSS) version 24 software. Descriptive statistics were used to summarize the results. Quality and safety, data were analyzed using SAS Software, version 9.4, and the chi-square test. From the total milk production, about 21.6% was lost due to postharvest losses. The study indicated that poor milk handling (28.4%), spoilage (20.3%), lack of milk marketing structure (22.6%), lack of cooling facilities (10.8%), lack of transportation (16.9%), and lack of roads (1%) were the major causes of milk postharvest loss in the study area. Within the study milk shed, the highest milk postharvest loss (40.5%) was observed in the Selale-Addis milk shed. The total annual milk production in the study milk sheds was estimated at 1,861,110 liters. Out of this total annual milk production, about 21.6% (401,999.76 liters) of the milk was lost due to lack of postharvest management. Considering the per capita milk consumption recommended by the World Health Organization (200 liters), the lost milk could satisfy the annual per capita milk consumption of 2,010 individuals. In terms of monetary value, the overall money lost along the market chain due to milk losses was 363,735.20 birr per year. Moreover, the total average amount of money lost due to annual milk loss from the total annual milk production was 22,351,187birr. The use of refrigerators, keeping milk in cold water, and storing milk in clean equipment were practiced as mitigation strategies for milk postharvest losses in the study area. The majority of the respondents (73%) practice the use of clean milk storage as a mitigation strategy for milk postharvest loss. The specific gravity of raw milk from Adama-Asela (1.035 g/cm3) and Ambo-Woliso (1.033 g/cm3) milk sheds were found to be within the normal specific gravity ranges of raw milk. The overall mean freezing point of raw milk was within the normal ranges of raw milk freezing point set by the Ethiopian Standard Agency. The overall mean pH value of raw milk in the milk sheds was lower than the normal pH value of fresh milk. The titratable acidity of raw milk is much higher than the normal fresh milk titratable acidity ranges. The overall mean moisture content, total solid, protein, lactose, and solid non-fat contents measured were within the normal range of raw cow milk set by the Ethiopian Standard Authority. The overall mean fat content of 3.43±0.05% was slightly below the minimum standards set for raw milk (3.5%) by the Ethiopian standard authority. A significantly higher total bacterial count (7.23 log 10 cfu/ml) was recorded for milk samples collected from retailers, while the lowest total bacterial count (6.46±0.14) was recorded for milk samples collected from producers. Significantly higher coliform counts were observed in milk samples collected from retailers (5.43±0.10 log10cfu/ml) and consumers (5.47±0.10 log10cfu/ml), indicating that coliform counts increase xvi along the value chains, which could be related to longer storage and poor handling of milk. Out of the total milk samples collected from the study milk sheds (117 samples), 47.9, 10.3, and 12.0% were positive for Salmonella spp., Staphylococcus aureus, and E. coli, respectively. The safety of milk from the study area was poor and could cause public health risks if raw milk produced and sold is consumed under the present production and handling conditions. The microbial quality of milk in the study milk sheds should be improved through improving the hygienic milk production, milk handling, milk storage, transportation, and marketing of milk in the dairy value chain. Thus, the findings of this study call for the enforcement of strict hygienic measures during production, transportation, and storage to improve the safety of raw cow milk produced and marketed in the study area. In conclusion, the total average milk postharvest loss 21.6% was observed in study milk sheds. Within the study of milk sheds, the highest milk postharvest loss (40.5%) was observed in the Selale-Addis milk shed, while the lowest 7.24% was in the Adama-Asela milk shed. The majority of the respondents 73% practice the use of clean milk storage as a mitigation strategy for milk postharvest losses. The microbial quality of raw milk was below standard. In addition, the safety of raw milk was poor and could cause public health risks. Therefore, enabling the actors in the market chain to engage in good hygienic milk production, handling, and storage, the provision of refrigerator, particularly solar-based refrigerators and appropriate milk equipment to milk producers, the use of appropriate milk transportation systems, and milk market regulation are recommended to reduce milk postharvest loss and thereby improve the income of the household and the per capita milk consumption in the study milk sheds. The stakeholder shall establish milk cooling centers at strategic locations of the major milk sheds and developing basic infrastructure, viz., roads and transportation facilities are important, to reduce milk postharvest losses and to increase the supply of milk to the market