The present study is concerned with the microbiological quality of commercially available yoghurt in Sylhet city, Bangladesh and to develop of new flavoured yoghurts. Two branded yoghurts (produced at large scale) indicated as BF and FK and three unbranded (produced at small scale) samples indicated as MM, SS and BMV were collected from the retail shops and microbial analysis were accomplished in the laboratory and finally new flavoured yoghurts were prepared and subjected to sensory evaluation. The study was designed by CRD with three replications. Data were analyzed by ANOVA techniques and comparisons of means were done by LSD, TUKEY, DMRT and GAMES-HOWELL multiple range test. Results revealed that all the samples were exceeded the standard plate count permissible limit (≥10⁷ cfug^-1 bacteria) for yoghurt. Thus, these yoghurts were considered as risky or harmful for consumption. Total Fungal Count (TFC) in the yoghurt samples BF, FK, MM and BMV showed 3.90×10⁴, 2.87×10⁴, 5.04×10⁴ and 4.60×10⁴ cfug^-1, respectively. All the samples were found in the range of acceptable or standard limit of TFC (≤10⁴ cfug^-1 fungus) except the sample SS (7.30×10⁶ cfug^-1) that was much higher than standard limit. Isolation of lactic acid bacteria (LAB) on MRS growth media observed that sample BF, MM and FK showed the growth of Lactobacillus spp. These isolated Lactobacillus spp bacteria was inoculated in pasteurized fresh milk, chocolate flavoured milk and orange flavoured milk and incubated at 37°C for 8 hours and new flavoured yoghurts were prepared. Organoleptic taste tests showed that among the developed products, chocolate yoghurt was highly acceptable by the panelists and liked very much (8.69).

Yoghurt, Microbial Quality, LAB, Bacterial Isolation, Yoghurts Product Development