Evaluation of three enrichment broths and six plating media for isolation and detection of salmonella in food stuffs

Salmonella is an important enteric pathogen which can transmitted via food and water. Therefore careful and rapid identification of this organism is very important. The aim of this study was to improve the results of the conventional methods for isolation and identification of this microorganism. 100 food samples were selected randomly, and incubated in Peptone Water (PW) at 37 degrees C for 24 hours (Pre enrichment). Rappaport -Vassiliadis Broth (RV) at 42°C, Tetrathionate Broth (TT) at 42°C and Fluid Selenite Cystine Broth (SC) at 37°C were the media used for enrichment and isolation of Salmonella. After 24 hours samples from each method were inoculated into six different media; Hektone Enteric agar (HE), Rambach agar (RA), CHROMagar Salmnella agar (CAS), Brilliant Green agar (BG), Salmonella – Shigella agar (SS)and Xylose – Lysine – Deoxycholate agar (XLD) and kept at 37°C for 18-24 hours. The suspected colonies from above mentioned media (3-5 colonies) were selected for biochemical tests in different ional media. 8 samples (8%) were contaminated with Salmonella. 57.4% of colonies in RV, 27.7% in SC and 14.9% in TT were positive. The highest and the lowest rates of isolation were (27.7%) and (6.4%) for RA and BG respectively. The results of this study showed that among five media used for isolation of Salmonella, RA medium was the best, while RV medium was suitable for revival of Salmonella.