摘要 : Yoghurt is usually made from recombined whole and skim milk powders, however some new dairy factories have started to use fresh milk for yoghurt production. This study evaluated the composition and microbiological quality of 96 pl... 展开 Yoghurt is usually made from recombined whole and skim milk powders, however some new dairy factories have started to use fresh milk for yoghurt production. This study evaluated the composition and microbiological quality of 96 plain set yoghurt samples during their storage. 4 batches of yoghurt (A and B prepared from recombined milk powder in different dairies, and C and D prepared from fresh milk in different dairies) were collected from a market in Khartoum State, Sudan, sampled and analysed in order to investigate the effect of milk type and storage at 4-7 degrees C for up to 9 days on yoghurt quality. Analysis of the yoghurt samples, revealed significant (<i>P</i> < 0.01) differences in total solids (TS), solids not fat (SNF), fat, protein and ash contents due to variations between the manufacturer and the type of milk used. The titratable acidity was not significantly affected by the type of milk used. The TS, SNF and protein contents and titratable acidity of the collected yoghurt samples were affected significantly (<i>P</i> < 0.01) during storage, whereas fat and ash contents were not significantly affected by the storage period. Counts of total bacteria, coliforms and yeast and other fungi were affected significantly (<i>P</i> < 0.05) by the manufacturer and the storage period. However counts of coliforms, and yeast and other fungi were not affected significantly by the type of milk used. It is concluded that the plain set yoghurt samples made from milk powder or fresh milk agree with Sudanese standards relating to the chemical composition of yoghurt. However, all the yoghurt samples had a high microbial load, hence, implementation of good hygienic conditions during yoghurt processing and storage are recommended to produce a good quality product. 收起