MILK HANDLING PRACTICES, MICROBIOLOGICAL QUALITY AND SAFETY OF RAW COW MILK ACROSS THE MILK SUPPLY CHAIN IN EASTERN ETHIOPIA

Abstract

Four interrelated studies were conducted to assess milk handling practices, microbiological quality and safety of raw cow milk across the milk supply chain in eastern Ethiopia. The first study evaluated hygienic cow milk production practices of producers, while the second study assessed milk postharvest handling practices of producers, collectors/transporters, vendors and consumers across the milk supply chain in the study area. Both studies employed cross sectional survey. The studies were based on a total of 160 (2 production systems * 5 PAs * 2 herd size groups * 8 households) milk producers, which were selected from Babile district using multistage stratified sampling technique. Moreover, a total of 54 collectors/transporters (5, 40, 9 from Jigjiga, Harar and Dire Dawa town, respectively), 152 vendors (40 from Bable, Harar and Dire Dawa town each and 32 from Jigjiga town) and 160 consumers (40 from each town) were selected using snowball sampling technique for the second study. Data from the selected actors were collected using questionnaire survey and field observation. The third and fourth studies were laboratory based evaluation of microbiological quality and safety, respectively, of raw cow milk across the milk supply chain in the study area. For these studies a total of 360 pooled raw cow milk samples (each with volume of 450 mL) were collected from the udders and equipment of producers in rural area of Babile district; equipment of collectors/transporters in Harar and Dire Dawa towns; equipment of vendors and consumers in Babile, Harar and Dire Dawa towns using the same sampling technique employed in the first and second studies. The results showed that the majority of the sampled household heads in pastoral (92.5-95.0%) and agro-pastoral (87.5-90%) production systems were illiterate. Similarly, the majority of milk producers (87.5-92.5%), collectors/transporters (88.9-100%), vendors (77.5-90.7%) and some consumers (37.5-47.5%) who were involved in milk postharvest handling operations were illiterate. Moreover, none of the respondents in the study area had training on hygienic milk production and postharvest handling practices. The study also revealed that all milking operations and the majority of milk postharvest handling practices were carried out by women. All respondent milk producers in the Babile district keep their cattle in separate corrals, which have poor drainage. The majority of sampled producers in pastoral (35.0%) and agro-pastoral (38.8%) production systems clean the barn once a week. The most commonly used milking equipment in the district is plastic container (50.6%) and the dominant milking equipment cleaning practice before milking was washing with cold water and detergent (39.4%). Moreover, the most commonly used milk handling equipment by producers (87.5-97.5%), traders (100%) and consumers (12.5-32.5%) was plastic jerry-cans. The milk handling equipment was commonly washed using warm water, detergent and sand; however, after washing, the equipment is not well protected from the risk factors by most respondents. The majority of sampled milk producers (55-65%), collectors/transporters (60-66.7%), and xiii some vendors (0-50%) and consumers (0-55%) use water from non-tap sources for hygienic practices. The overall mean total aerobic meshophilic bacterial count (TAMBC), total coliform count (TCC), yeast count (YC), mould count (MC), Escherichia coli (E. coli) count and Staphylococcus aureus (S. aureus) count for udder milk samples were 6.02, 4.23, 2.57, 2.67, 3.33 and 3.09 log10 cfu mL-1, respectively. The mean values of TAMBC, TCC, YC, MC, E. coli count and S. aureus count for samples collected from the equipment of producers were 7.17, 5.86, 3.46, 3.70, 4.46 and 4.03 log10 cfu mL-1, respectively. The mean TAMBC, TCC, YC, MC, E. coli count and S. aureus count for samples collected from the equipment of collectors/transporters were 7.96, 6.49, 3.99, 4.37, 5.54 and 5.04 log10 cfu mL-1, respectively. The mean counts for samples collected from the equipment of vendors were 8.78, 7.32, 4.98, 5.04, 6.30 and 5.69 log10 cfu mL-1 for TAMBC, TCC, YC, MC, E. coli and S. aureus, respectively. The mean values of TAMBC, TCC, YC, MC, E. coli count and S. aureus count for samples collected from the equipment of consumers were 8.82, 7.37, 5.10, 5.11, 6.32 and 5.75 log10 cfu mL-1, respectively. There was a significant difference in mean TAMBC, TCC, YC, MC, E. coli count and S. aureus count across the milk sources (cow's udder, equipment of producers, collectors/tranpsorters, vendors and consumers) except for the difference between vendors and consumers. No Salmonella species was detected in all raw milk samples collected from the udders; whereas, it was detected in 14, 18, 25 and 27% of raw milk samples collected from the equipment of producers, collectors/transporters, vendors and consumers, respectively. In general, the study indicated that hygienic practices performed during cow milk production and postharvest handling in the study area was substandard. Similarly, the raw cow milk samples collected from all milk sources were contaminated with aerobic mesophilic, coliforms, E. coli and S. aureus bacteria as well as with yeasts and molds with counts exceeding the respective acceptable limits. Moreover, some raw milk samples obtained from the equipment of producers, collectors/transporters, vendors and consumers possessed detectable levels of Salmonella species. This suggests the need for improving hygienic practices through awareness creation and capacity development of milk producers, traders and consumers on hygienic practices essential for safe milk production and handling. Moreover, introduction of pertinent interventions such as milk cooling facilities, organized and efficient milk storage and transportation systems at all critical levels are highly important. Providing better quality water especially at producer’s level is also very crucial.