Abstract Five Lactobacillus plantarum strains (which were previously isolated from Turkish pastırma), were evaluated for the possibilities of using in the food industry. Antimicrobial properties, metabolic activities, exopolysaccharide production and antibiotic resistance were investigated. It was also assessed probiotics features such as adhesion ability, survival in simulated gastric environment and acid tolerance analysis. Antimicrobial activity was characterized based on effects of several enzymes, different temperature and pH. All strains showed remarkable antimicrobial activity and antimicrobial substances were found resistant to enzymes, high temperature and low pH. Metabolic activities and exopolysaccharide production of the strains were found relatively weak. Determinate to antibiotic susceptibility patterns 14 different antibiotics used and strains were found reliable in terms of transferable resistance genes except for erythromycin. All strains showed resistance to acidic condition and gastric environment. However, adhesion ability of strains was found relatively low. All findings showed that, these strains potential candidate for use in food industry especially as natural food preservatives because of antimicrobial activity capacity and one strain (S2) have remarkable potential to use as starter cultures or probiotics.

Abstract The survival of Escherichia coli O157: H7 and Staphylococcus aureus, which are foodborne pathogens was investigated during fermentation and storage of kefir. The kefir grains were inoculated with 5% of the whole fat UHT cow milk and the E. coli O157: H7 and S. aureus cultures were added separately to give 105 cfu mL-1 and left to incubate at 22 °C for 24 hours at first stage. During the incubation, the bacteria and yeast counts, pH and titratable acidity amounts were determined. In the second stage, E. coli O157: H7 and S. aureus cultures were separately added to produce 105 cfu mL -1 of kefir and was stocked at 5 °C for 3 days. Every day samples were taken and the same tests were done. During fermentation, in all samples the initial while TA was 0.14%, the fermentation was 1.0% and 1.01% at the end. The kefir samples were pH 4.5 at the end of the 3 day period of storage. S.aureus was significantly inhibited while E.coli was not inhibited during the fermentation process. During storage, E. coli O157: H7 and S. aureus were inhibited within 2 days. The kefir has the quality of being a healthy product during fermentation and storage.

The occurrence of Aeromonas spp. in the Porsuk River, public drinking water and tap water in the City of Eskisehir (Turkey) was monitored. Fresh water samples were collected from several sampling sites during a period of one year. Total 102 typical colonies of Aeromonas spp. were submitted to biochemical tests for species differentiation and of 60 isolates were confirmed by biochemical tests. Further identifications of isolates were carried out first with the VITEK system (BioMe˜rieux) and then selected isolates from different phenotypes (VITEK types) were identified using the DuPont Qualicon RiboPrinter® system. Aeromonas spp. was detected only in the samples from the Porsuk River. According to the results obtained with the VITEK system, our isolates were 13% Aeromonas hydrophila, 37% Aeromonas caviae, 35% Pseudomonas putida, and 15% Pseudomonas acidovorans. In addition Pseudomonas sp., Pseudomonas maltophila, Aeromonas salmonicida, Aeromonas hydrophila, and Aeromonas media species were determined using the RiboPrinter® system. The samples taken from the Porsuk River were found to contain very diverse Aeromonas populations that can pose a risk for the residents of the city. On the other hand, drinking water and tap water of the City are free from Aeromonas pathogens and seem to be reliable water sources for the community.