Isolation and Molecular Identification of Salmonella spp. from Local Dairy Products in Maragheh City in 2015 (Iran)

Salmonella is one of the authentic bacteria found in food and raw materials. The existence of this bacterium in food, in addition to causing disease, can lead to drop in production quality and decrease in economic growth of the country. The aim of this research was to isolate and identify Salmonella spp. from local dairy products in Maragheh city.
In this cross sectional study, a total of 100 samples, were randomly selected from local dairy products, including curd, cheese, butter, dough, and ice cream (20 samples of each). First, the samples were cultured and tested by standard method, then, biochemical and serotyping complementary tests, were performed to detect Salmonella bacterium, and polymerase chain reaction (PCR) using hilA gene primers, was performed for molecular confirmation of the isolates from local dairy products. Antibiogram test was carried out on the obtained isolates.
Overall, 3% of all samples, were contaminated with Salmonella. Two Salmonella cases (10%), including B and D serogroups were isolated from 20 local crud samples and 1 Salmonella case (5%) of C serogroup, was isolated from 20 local cheese. No Salmonella was isolated from local butter, dough, and ice cream samples. Among the obtained isolates, the highest susceptibility was related to trimethoprim-solfamethoxazole antibiotic, and the highest resistance was related to nitrofurantoin antibiotic.
The results of this study showed that in order to prevent poisoning from local dairy products, pasteurization of milk and its products, personal hygiene compliance, and control of health monitoring of production and distribution centers, are necessary.