Determination of the biochemical properties and antibacterial activity of lactic acid bacteria isolated from different regional dairy products on some foodborne pathogens

During production, foods are contaminated by pathogenic microorganisms due to different reasons, and thus the deterioration process in foods is accelerated. If these foods are consumed, they cause some food-borne diseases. Physical and chemical methods are used to protect foods from this contamination. Among these, although chemical preservatives are generally used, reliable preservatives are more important because there are negative thoughts and prejudices by the consumer. In this study, the effect of compounds such as organic acids, hydrogen peroxide and bacteriocins produced by lactic acid bacteria isolated from milk and dairy products (cheese, yoghurt, butter) that we consume in our daily lives on pathogenic microorganisms and antibiotics were investigated in the search for reliable preservatives. In our research, traditionally produced dairy products in Afyonkarahisar province and its surrounding villages; 30 different yoghurt, cheese and butter samples were taken. As a result of the isolation procedures made from the samples taken, 20 different lactic acid bacteria were isolated and the isolate was confirmed with API 50 CHL and API 20 STREP test kits. The 20 different lactic acid bacteria identified were 100% gram positive, 100% catalase negative, %95; Developing in an environment containing %4 salt, %90; Developing in an environment containing %6 salt, %40; Developing in an environment containing %8 salt, at a rate of %35; Their ability to grow in an environment containing %10 salt has been determined. In addition, at the rate of %65; Developing in an environment containing 4,8 pH, %75; Developing in an environment containing 6,5 pH, at a rate of 45%; Their ability to grow in an environment containing 9,8 pH has also been determined. In addition to these, at the rate of %60; While developing at 10ºC, %100; It was determined that it developed at 37ºC and %55 at 45ºC. While the lipolytic activity of lactic acid bacteria isolated in our study was %80 in the analyzes performed in Blue Agar medium, it was detected in %60 in the analyzes performed in 20/80 MRS Agar medium. While its proteolytic activity was detected at a rate of %40 in KK Agar medium, it was detected at a rate of %5 in MRS agar medium containing gelatin. Nitrate reductase activity was found to be %55. The antibacterial effect of isolated 20 different lactic acid bacteria on 10 different pathogenic bacteria and antibiotic resistance on 11 different antibiotics were determined. The highest antimicrobial effect; It was detected in Pediococcus acidilactici specimen against Salmonella Typhimurium with a zone diameter of 16,12 mm.