Microbial and Chemical Characteristics of Doogh (Iranian Fermented Milk Drink)

Regarding the increasing public health concerns about the safety of foodstuffs, the current survey was designed to argue the presence of preservatives (e.g., sodium benzoate (SB), potassium sorbate (PS), and natamycin) and also the level of salt and fungi in 148 samples of yoghurt drink "Doogh."

The enumeration of fungi and determination of salt content of samples were performed according to the standard procedures. Preservative determination was performed by reverse phase high-performance liquid chromatography with UV detection (RV-HPLC-UV).

0.1% of the total analyzed samples was above the permitted level of Iranian standard for SB (0%), while PS was not detected in any of them. Furthermore, natamycin in 0.11% of the analyzed samples had more than the permissible level of Iranian standard. Additionally, about 15% of the tested samples was higher than the Iranian standard level for fungi (<102 CFU/mL). The average amount of salt in the tested Doogh samples and also in the examined Kefir samples was significantly (P < 0.001) lower than the standard amount of salt (<0.8 g/100).

In conclusion, the quality of Doogh and Kefir samples were acceptable in terms of salt content. Kefir had a significantly (P ≤ 0.001) lower amount of salt in comparison with Doogh. Taken together, underlining the results of the present study, no significant public health concern would exist respecting the mentioned additives.