Evaluation of physico-chemical, nutritional and microbiological quality of raw cow’s milk usually Consumed in the central part of Côte d’Ivoire

Abstract

Cow’s milk is by far the principal type of milk used throughout the world. Three systems of husbandry in Côte d’Ivoire produce raw milk. This production is always consumed directly by people, mainly children (orphans) although it presents real sanitary risks. In order to evaluate quality of these cow’s milks, several samples were collected during a three month period (April to June 2009) at three cattle farms from where consumers got  supplies. Physicochemical, nutritional, microbiological properties of the milks were studied. Results showed that viscosity, dry matter, fat and chloride contents of milk of traditional cows, N’dama and Zebu are higher than the standard values. pH values and acid content of N’dama milks are identical to those of standards. Zebu milk values for these two parameters are higher than standards: 6.59 ± 0.30 > 6.50 ± 0.30 %; 21.0 ± 1.0 > 17.0 ± 1.0 °D, respectively. However,conductivity, protein content, lactose and ash content of these milks are lower than those of standards. Comparing the characteristics of milks from various farms showed that farm C had higher content of fat (5.00 ± 1.18 > 3.25 ± 0.25), titrable acidity (20.40 ± 0.68 > 17.0 ± 1.00), dry matter (174.00 ± 18.42 > 127.50 ± 2.50), chloride (2.66 ± 0.56 > 1.60 ± 0.20) and viscosity (1.60 ± 0.20 > 2.00 ± 0.30) compared with the standard values. There is no significant difference (p >0.05) in viscosity value, chloride and protein contents among the  milks of the three farms. Conductivity, ash and protein content showed lower values than those of the standards. Microbiological result showed that all of the raw milks were contaminated, but the milks from farms B and C were more contaminated. Staphylococcus aureus count in milk of these farms were 8 x102 and 65 x102 cfu/ml, 5.1 x105 and 251.2 x105 cfu/ml for TVBC and total coliform were 3.85 x103 and 6.91 x103 cfu/ml. These values are higher than those of the standards. In short, milk produced in the farms has acceptable physico-chemical, nutritional and properties but bad microbiological qualities.

Key words: raw milk, cows, quality, hygiene