Effect of Lactobacillus plantarum on microbial population of Iranian fermented pickle

Pickle fermentation is a natural process in which microorganisms could affect the quality of the product. Amongst، Lactobacillus plantarum strains that improve the quality of fermented pickle. In this study، in order to produce safe and desirable fermented pickle، local cucumbers were immersed in 5% and 7% (w/v) brine solutions. The samples were inoculated with 0، 4 ×106، 4 ×107 and 6 ×108 cfu/ml of L. plantarum. The samples were kept at ambient temperature for 15 days followed by 30 days storage at 4 °C and 25 °C. The bacterial populations were analyzed during the aforementioned stages of fermentation and storage. According to the results، the maximum quantity (8. 57 log10 cfu/ml) of L. plantarum was observed in the 9 day of fermentation and in the samples inoculated with 6 ×108 cfu/ml and kept in 5% brine solution. Moreover، compared to the other samples، the population of yeasts and aerobic mesophilic count were the least in the samples inoculated with 6 ×108 cfu/ml of L. plantarum and stored in 7% brine solution. During the storage period، the population of L. plantarum، yeasts and aerobic mesophilic in the samples stored at 25 °C were higher than the samples stored at 4 °C. Results revealed that in the 30 day of storage، the highest load (5. 47 log10 cfu/ml) of L. plantarum was observed in the samples kept in 7% brine solution at 4 °C. It was concluded that providing the condition that favors the appropriate growth of L. plantarum could help to hinder the growth of undesirable organisms in fermented pickle.