Traditional yogurt dilemma; rich flavor vs. microbial safety: An investigation on Volatile Aroma Profiles, Chemical, and Microbiological Qualities of Traditional Yogurts

This study aimed to bring out chemical, physical, and microbiological quality together with volatile aroma profiles of traditional yogurts collected from the highlands of Ordu and Giresun cities in the Black Sea Region (Turkey). For this purpose, 24 traditional yogurts, 20 of which were produced from cow milk and the remaining were produced from buffalo milk, were collected and analyzes were performed. The average dry matter, protein, fat, pH, total acidity (lactic acid%), viscosity (10 °C), and syneresis values for cow milk and buffalo milk yogurts were 12.68 vs. 14.44%, 3.51 vs. 4.13%, 4.51 vs. 6.55%, 3.80 vs. 3.78, 1.32 vs. 1.60%, 241.09 vs. 1009.21 cP, and 17.43 vs. 9.02%, respectively. The buffalo milk yogurts had higher dry matter, protein, fat, viscosity but lower syneresis values compared to those of cow milk yogurts. The lactic acid bacteria counts were under the required number of 107 for cow yogurts while yeast & mould counts were over 105 for both cow and buffalo yogurts. Moreover, five of the cow yogurts were found to have coliforms and one being contaminated with Escherichia coli indicating unhygienic production conditions. All yogurts contained acetaldehyde, acetoin, ethanol, hexanoic acid, octanoic acid, hexanal, 2-Heptanaone, and 2-Nonanone while diacetyl could not be detected in any yogurt samples. Regarding their compositional values, homemade yogurts were acceptable however they were not appropriate for consumption microbiologically and require improved hygienic conditions for healthier products.