نفیسه دعوتی

چون در انتقال چکیده فارسی ازفایل کنگره کلمات بهم ریخته شد چکیده انگلیسی درج گردید Pickled vegetables is a traditional fermented food which are produced in Iran. The aim of this study was evaluation of changes of pathogenic bacteria and several lactic acid bacteria populations of pickled vegetables during fermentation.The pickled vegetables were prepared in three replications and samples were collected during 40 days of fermentation under aseptic conditions. Then, appropriate dilutions of samples were plated onto seven groups of culture media including VRBA for Coliform, Pseudomonas agar for pseudomonas, Kanamycin aesculin azide agar for Enterococcus, De Man, Rogosa and Sharpe agar for Lactobacillus, Mannitol salt agar for Staphylococcus aureus, Potato dextrose agar for Fungi and Plate count agar for total bacterial count. Plates were incubated at 22°C (Fungi) and 37°C (other bacteria) for 48. Also, pH and acidity changes were measured during fermentation. The total bacterial count was increased by 9.10 log units, Coliform was reduced by 5.46 log units, Lactobacillus was increased by 5.70 log units, Enterococcus was increased by 3.14 log units, Staphylococcus aureus was reduced by 3.51 log units, Fungi was reduced by 2.40 log units and pseudomonas was reduced by 3.82 log units. After 40 days of fermentation period, pH was reduced by 1.21 unit and acidity (lactic acid) was increased from 0.69 to 2 mg/ml. Based on results of bacterial count during fermentation, Lactic acid bacteria including Lactobacillus and Enterococcus were increased and pathogenic bacteria and Fungi were reduced duiring fermentation. Reduction of pH, increasing of acidity, presence of lactic acid bacteria and their antimicrobial metabolites can cause reduction of pathogenic bacteria population in final product.