Evaluation of Microbiological quality and determination of starch gelatin and natamycin content in yoghurt from Turkish market

Yoghurt is one of the most popular dairy products, is considered as a healthy food with its high protein and fat content. Starch and gelatin may be used as gelling, thickening agent in dairy products. Natamycin, a prohibited preservative in yoghurt, is effective on yeasts and moulds. In this study, the presence of gelatin, starch and natamycin was investigated and microbiological quality of yogurts were examined in 14 national and 6 local brands available in the Turkish market. No gelatin and starch were found in yoghurt, and natamycin was detected in 5 of the 20 samples. Natamycin concentrations observed in samples ranged from 1,3 to 16,5 ppm. In 4 of the 5 natamycin using brands also revealed higher yeast counts than non-using ones. No E. coli was detected. 4 samples of yoghurts were contaminated by total coliforms, within only one sample was above the critical limit of official Turkish legislation.