Identification of selected Lactobacillus strains isolated from Siahmazgi cheese and study on their behavior after inoculation in fermented-sausage model medium

Seventy-one lactic-acid bacteria (LAB) were isolated from a sample of “Siahmazgi”, an Iranian traditional cheese. Lactobacilli were then screened for some technological properties such as rapid and adequate production of lactic acid, growth in different salt concentrations, gas production from carbohydrates, catalase activity and antimicrobial activity. Finally, the selected lactobacilli were tested for their growth profile in a fluid model-medium modified according to the special conditions of fermented sausages. LSCD5, LSCD7, LSCD10, LSCD11 and LSCD14 showed high acidifying activity, and reduced the pH of MRS broth medium to ∼4.0 in 24 h at 30 °C and in 48 h at 20 °C. These strains were identified by biochemical and molecular methods (16s rDNA sequencing) as Lactobacillus plantarum . The screened lactobacilli, except LSCD11, were able to grow at a high salt concentration of 10%. They also showed antimicrobial activities against Listeria monocytogenes , Staphylococcus aureus and Escherichia coli O157:H7. Relatively acceptable souring properties and good growth properties in simulated fermented sausage (SFS) medium were found for LSCD7 and LSCD14, with maximum numbers of 7.21, and 7.99 log CFU/ml, respectively. As a result, LSCD7 and LSCD14 exhibited the best technological properties to act as starter cultures for manufacturing fermented meat products.