| Abstract | Cilj ovog rada bio je ispitati probiotička svojstva bakterijskih sojeva D3, D4, D6, M5 i MA3, izoliranih iz tradicionalnog svježeg i dimljenog sira. Ispitani bakterijski sojevi pokazuju podnošljivost prema visokoj koncentraciji vodikovih iona (pH = 2,0) i djelovanju pepsina u simuliranom sekretu želuca. Neosjetljivi su prema djelovanju enzima gušterače i pokazuju otpornost prema djelovanju žučnih soli (3,0 mg/ml). Bakterijski sojevi su uglavnom osjetljivi na većinu ispitanih antibiotika, osim na norfoksacin na koji su rezistentni svi ispitani sojevi osim bakterijskog soja MA3, streptomicin na koji je rezistentan bakterijski soj D6, ciprofloksacin na koji su rezistentni bakterijski sojevi D4 i M5, te vankomicin na koji su rezistentni sojevi D3, D4 i M5. Svi ispitani bakterijski sojevi pokazuju visok postotak autoagreagacije te mogućnost koagregacije s drugim bakterijama mliječne kiseline dok su sojevi D3, D6, M5 i MA3 koagregirali i s ispitanim test-mikroorganizmima. Svi ispitani bakterijski sojevi pokazuju antimikrobno djelovanje prema test–mikroorganizmima mikroorganizmima Staphylococcus aureus 3048, Staphylococcus aureus K-144, Escherichia coli 3014, Salmonella enterica serovar Typhimurium FP1, Bacillus cereus TM2 i Bacillus subtilis ATCC 6633, što omogućuje kompetitivnu ekskluziju nepoželjnih mikroorganizama, kada se primjene kao starter kulture u fermentiranim proizvodima. Sojevi D3, D4 i D6 pokazuju i dodatno, bakteriocinsko djelovanje prema srodnim bakterijskim vrstama. Na temelju fermentacijskih profila ugljikohidrata, definiranih pomoću API testa, ispitivani sojevi identificirani su kao Lactobacillus plantarum i Lactobacillus pentosus vrste. Bakterijski sojevi su preživjeli proces liofilizacije u visokom broju (cca 109 CFU/ml), što je značajno s tehnološkog aspekta proizvodnje starter kultura za industrijsku primjenu. |
| Abstract (english) | The aim of this study was to investigate the probiotic properties of bacterial strains D3, D4, D6, M5 and MA3 isolated from traditionally made fresh dried and smoked cheeses. Investigated bacterial strains have shown tolerance to high concentration of hydrogen ions (pH = 2.0) and pepsin action in simulated gastric secrete. They were insensitive against the action of pancreatic enzymes and have shown resistance against the activity of bile salts (3.0 mg/ml). Most tested antibiotics are inhibitory against tested bacteria, while D3, D4 and M5 strains have shown resistance to vancomycine; D4 and M5 strains have shown resistance to ciprofloxacin; D3, D4, D5 and M5 strains have shown resistance to norfoxacin: D4 and M5 strains have shown resistance to ciprofloxacin; and D6 strain has shown resistance to streptomycin. High percent of autoaggregation and coaggregation with different lactic acid bacteria by tested bacterial strains was obtained while D3, D6, M5 and MA3 strains coaggregated also with test-microorganisms. These autochthonous isolates have shown strong antimicrobial activity against different test – microorganisms, what enables them a competitive exclusion of undesirable microorganisms, when applied as starter cultures. D3, D4 and D6 strains have shown additional bacteriocinogenic activity against similar bacterial species. Tested strains were identified according to the API sugar fermentation profiles as members of Lactobacillus plantarum and Lactobacillus pentosus strains. Isolated bacteria have successfully survived the freeze-drying process (108~109 CFU/ml), what is important technological property in the industrial production of starter cultures. |
