Microbial safety, physical properties and chemical composition of cow milk in Ethiopia, A review

Ethiopia takes first place in the cattle herd population from Africa. However the production and productivity and quality of milk are low due to various factors such as genetic makeup of the breeds, inadequate and poor quality feed and water resources, and lack of knowledge for appropriate hygienic practices in milk production. Cow milk is recognized as complete human food as it constitutes principal nutritionally important components such as water (۸۷.۲%), protein (۳.۵%), fat (۳.۷%), milk sugar or lactose (۴.۹%), ash (۰.۷%), and dry matter (۱۲.۸%). This, on the other hand, makes milk a suitable medium for the growth and multiplication of a variety of pathogenic and spoilage microflora. Research reports of microbial and physicochemical qualities of cow milk published in different Journals have been reviewed in this paper. Studies show that a total bacterial load range of ۴.۵۷ and ۹.۸۲ log CFU ml-۱ has been reported in Hawassa City and Gurage Zone in Southern Ethiopia, respectively as minimum and maximum values. Whereas, a total coliform count of ۶.۱۹ log CFU ml-۱ was reported in Yabello, Borena Zone as maximum contamination. The minimum value was recorded in Gurage Zone being ۴.۰۳ log CFU ml-۱. Yeast and mold contamination was also widely studied and reports showed that the highest load of ۷.۲۴ log CFU ml-۱ was recorded in Abuna Gindeberet District of West Showa Zone. A count as low as ۰.۶۲۲ log CFU ml-۱ was reported in the Dawa Chefa District of Amhara Region. As major chemical constituents of cow milk, fat (۴.۱۹-۶.۰۲ %), protein (۳.۲۰-۳.۹۸ %), lactose (۳.۷۹-۵.۳۹ %), SNF (۷.۶۰-۹.۷۷ %), ash (۰.۶۸-۰.۸۰ %), total solids (۱۲.۰۲-۱۵.۴۷ %) and a titratable acidity (۰.۱۶-۰.۳۸ %) were reported in different parts of the country. Moreover, physical parameters of pH and specific gravity ranges of ۶.۳۰-۶.۴۸ and ۱.۰۲۲-۱.۰۶ gm/cm۳ were recorded from milk samples studied in parts of Ethiopia. From most of the studies, it could be observed that most of the milk samples are of substandard quality in terms of microbial load according to standards set by different Organizations rendering them unsafe and hazardous for raw consumption and unsuitable for further processing. This indicates the high prevalence of inadequate hygienic practices among the dairy producers which in turn necessitates the delivery of training on the general pre and post-production management of cow milk.Ethiopia takes first place in the cattle herd population from Africa. However the production and productivity and quality of milk are low due to various factors such as genetic makeup of the breeds, inadequate and poor quality feed and water resources, and lack of knowledge for appropriate hygienic practices in milk production. Cow milk is recognized as complete human food as it constitutes principal nutritionally important components such as water (۸۷.۲%), protein (۳.۵%), fat (۳.۷%), milk sugar or lactose (۴.۹%), ash (۰.۷%), and dry matter (۱۲.۸%). This, on the other hand, makes milk a suitable medium for the growth and multiplication of a variety of pathogenic and spoilage microflora. Research reports of microbial and physicochemical qualities of cow milk published in different Journals have been reviewed in this paper. Studies show that a total bacterial load range of ۴.۵۷ and ۹.۸۲ log CFU ml-۱ has been reported in Hawassa City and Gurage Zone in Southern Ethiopia, respectively as minimum and maximum values. Whereas, a total coliform count of ۶.۱۹ log CFU ml-۱ was reported in Yabello, Borena Zone as maximum contamination. The minimum value was recorded in Gurage Zone being ۴.۰۳ log CFU ml-۱. Yeast and mold contamination was also widely studied and reports showed that the highest load of ۷.۲۴ log CFU ml-۱ was recorded in Abuna Gindeberet District of West Showa Zone. A count as low as ۰.۶۲۲ log CFU ml-۱ was reported in the Dawa Chefa District of Amhara Region. As major chemical constituents of cow milk, fat (۴.۱۹-۶.۰۲ %), protein (۳.۲۰-۳.۹۸ %), lactose (۳.۷۹-۵.۳۹ %), SNF (۷.۶۰-۹.۷۷ %), ash (۰.۶۸-۰.۸۰ %), total solids (۱۲.۰۲-۱۵.۴۷ %) and a titratable acidity (۰.۱۶-۰.۳۸ %) were reported in different parts of the country. Moreover, physical parameters of pH and specific gravity ranges of ۶.۳۰-۶.۴۸ and ۱.۰۲۲-۱.۰۶ gm/cm۳ were recorded from milk samples studied in parts of Ethiopia. From most of the studies, it could be observed that most of the milk samples are of substandard quality in terms of microbial load according to standards set by different Organizations rendering them unsafe and hazardous for raw consumption and unsuitable for further processing. This indicates the high prevalence of inadequate hygienic practices among the dairy producers which in turn necessitates the delivery of training on the general pre and post-production management of cow milk.

Keywords:

Cow milk , microbial safety , chemical composition , physical properties