Physicochemical, microbiological and sensory properties of Sudanese yoghurt (zabadi) made from goat's milk

Physicochemical, microbiological and sensory attributes of fresh and cold-stored (5-15 days) fermented zabadi from goat's milk were analysed and then compared with those of cow's milk. Results indicated that the gross nutrients of fresh goat's milk changed after processing. Zabadi fermentation significantly decreased the lactose content and pH of the fresh milk in both zabadi types. Cow-milk zabadi was more viscous than goat-milk zabadi. Cold storage resulted in significant changes in gross composition of both zabadi types, in particular after 10 days of storage. Lactose and pH decreased further if the storage period was prolonged. Lactobacillus spp. and Streptococcus spp. are the main active organisms in goat-and cow-milk zabadi. The number of total bacteria and yeast increased significantly within 10 days of storage, decreasing thereafter. Staphylococcus aureus and Salmonella spp. were absent. Coliforms and faecal coliforms were detected in both zabadi types; however, they disappeared after 5 days of storage. Goat-milk zabadi showed significantly lower sensory scores than cow-milk zabadi. Both zabadi types can withstand storage to a maximum of 10 days, with the sensory scores decreasing thereafter.