The use of probiotics in the diet of bivalves poses a great potential in aquaculture as an alternative to antibiotics. The aim of this study was to assess the effect of Lactiplantibacillus plantarum I on the phenolic content and... more
The use of probiotics in the diet of bivalves poses a great potential in aquaculture as an alternative to antibiotics. The aim of this study was to assess the effect of Lactiplantibacillus plantarum I on the phenolic content and antioxidant capacity (AC) of queen scallop extracts after one month of feeding. Total phenols (TP) ranged from 28.17 ± 3.11 to 58.58 ± 8.57 mg GAE/100 g, total non-flavonoids (TNF) from 23.33 ± 3.66 to 36.56 ± 9.91 mg GAE/100 g, and total flavonoids (TF) from 10.56 ± 5.57 to 30.16 ± 1.69 mg CE/100 g. AC was assessed via three different methods: the ferric-reducing ability of plasma assay (FRAP), 2,2′-azino-bis (3-ethylbenzothiazoline-6-sulfonic) acid assay (ABTS), and 2,2-diphenyl-1-picryhydrazyl assay (DPPH). FRAP values ranged from 0.13 ± 0.03 to 0.17 ± 0.02 µM AA/g, ABTS from 0.68 ± 0.11 to 2.79 ± 0.34 µM AA/g, and DPPH from 1.75 ± 0.17 to 2.98 ± 0.53 µM AA/g. Among all extracts, the best phenolic content and AC were observed in water extracts from queen ...
Research Interests:
By increasing the resistance of seeds against abiotic and biotic stress, the possibility of cereal mold contamination and hence the occurrence of secondary mold metabolites mycotoxins decreases. The use of biological methods of seed... more
By increasing the resistance of seeds against abiotic and biotic stress, the possibility of cereal mold contamination and hence the occurrence of secondary mold metabolites mycotoxins decreases. The use of biological methods of seed treatment represents a complementary strategy, which can be implemented as an environmental-friendlier approach to increase the agricultural sustainability. Whereas the use of resistant cultivars helps to reduce mold growth and mycotoxin contamination at the very beginning of the production chain, biological detoxification of cereals provides additional weapons against fungal pathogens in the later stage. Most efficient techniques can be selected and combined on an industrial scale to reduce losses and boost crop yields and agriculture sustainability, increasing at the same time food and feed safety. This paper strives to emphasize the possibility of implementation of biocontrol methods in the production of resistant seeds and the prevention and reductio...
Research Interests:
Rezultati brojnih istraživanja ukazuju na to da ribe i školjkaši posjeduju različitu populaciju bakterija na koži, škrgama te u probavnom traktu. Pored toga, unutarnji organi (bubrezi, jetra i slezena) zdrave ribe mogu također sadržavati... more
Rezultati brojnih istraživanja ukazuju na to da ribe i školjkaši posjeduju različitu populaciju bakterija na koži, škrgama te u probavnom traktu. Pored toga, unutarnji organi (bubrezi, jetra i slezena) zdrave ribe mogu također sadržavati bakterije. Stoga je cilj ovog istraživanja bio izolirati i identificirati mikrobnu populaciju lubina (Dicentrarchus labrax), dagnji (Mytilus galloprovincialis) i kamenica (Ostrea edulis) Jadranskog mora tijekom zimskog perioda. Od ukupno 15 uzoraka 5 je uzoraka bilo kontaminirano bakterijama iz roda Vibrio, iz 4 uzorka je izolirana E. coli, 5 uzoraka su bila pozitivna na sulfitoreducirajuće klostridije dok je Pseudomonas aeruginosa dokazan samo u uzorcima dagnji i kamenica. U svim uzorcima lubina su dokazane enterobakterije. U niti jednom uzorku lubina i školjkaša nije dokazana prisutnost bakterija iz roda Salmonella kao ni Listeria monocytogenes. Bakterije mliječne kiseline su izolirane iz samo jednog uzorka lubina i to rod Lactobacillus. Fizikalno...
Research Interests:
Research Interests:
Sir je visoko cijenjeni mlijecni proizvod u mnogim zemljama svijeta, a posebna pažnja pridaje se tradicionalnim sirevima, koji nisu samo hrana vec i dio kulture i obilježja neke zemlje. Zahvaljujuci zemljopisnom položaju i... more
Sir je visoko cijenjeni mlijecni proizvod u mnogim zemljama svijeta, a posebna pažnja pridaje se tradicionalnim sirevima, koji nisu samo hrana vec i dio kulture i obilježja neke zemlje. Zahvaljujuci zemljopisnom položaju i klimatsko-vegetacijskoj raznolikosti Republike Hrvatske, u pojedinim regijama razvijena je proizvodnja razlicitih tradicionalnih sireva uz upotrebu zacina. Kod proizvodnje sireva sa zacinima, zacini se dodaju ili u sir koji se potom oblikuje, ili se sir omata liscem zacinskog bilja, ponekad se zacini nanose na povrsinu sira, a samo u rjeđim slucajevima zacini se stavljaju u sam grus. Dodatak zacina u sirarstvu pridonosi poboljsanju senzorskih karakteristika, povecanju stabilnosti i roka trajanja sira te povecanju nutritivne vrijednosti sira. Kemijski sastav zacina je kompleksan i svaki zacin ima neki specifican i dominantan sastojak koji pridonosi aromi proizvoda i/ili antimikrobnom i antioksidacijskom djelovanju zacina. U ovom radu dan je pregled zacinskog i arom...
Research Interests:
Mikotoksini predstavljaju prirodne toksine koji učestalo kontaminiraju hranu i hranu za životinje, a primarno ih sintetiziraju plijesni iz rodova Aspergillus, Penicillium, Fusarium, Alternaria i Claviceps. Ove tvari predstavljaju vrlo... more
Mikotoksini predstavljaju prirodne toksine koji učestalo kontaminiraju hranu i hranu za životinje, a primarno ih sintetiziraju plijesni iz rodova Aspergillus, Penicillium, Fusarium, Alternaria i Claviceps. Ove tvari predstavljaju vrlo stabilne spojeve, otporne na različite uvjete proizvodnje, prerade i skladištenja hrane. Mikotoksini mogu prouzročiti niz štetnih učinaka po zdravlje ljudi i životinja, tzv. mikotoksikoze, uključujući karcinogenost, mutagenost, genotoksičnost, imunotoksičnost, neurotoksičnost, hepatotoksičnost, nefrotoksičnost, te druge, pri čemu često istovremeno djeluju na više ciljnih mjesta u organizmu, u ovisnosti o toksičnosti samog mikotoksina te dozi i vremenu izloženosti. Za veliki broj mikotoksina još uvijek nema dovoljno dokaza o njihovim štetnim učincima na ljudsko zdravlje, ali se temeljem utvrđene osjetljivosti različitih životinjskih vrsta pretpostavlja da i u ljudi mogu izazvati slična djelovanja. Ujedno, za većinu mikotoksina koji se učestalo zajedničk...
Research Interests:
Research Interests:
Research Interests:
Komercijalni pekarski kvasac je aktivna biomasa kvasca Saccharomyces cerevisiae kojoj se tijekom procesa proizvodnje, distribucije i skladistenja pridružuju i drugi nenamjenski mikroorganizmi. U radu je ispitana mikrobioloska kvaliteta... more
Komercijalni pekarski kvasac je aktivna biomasa kvasca Saccharomyces cerevisiae kojoj se tijekom procesa proizvodnje, distribucije i skladistenja pridružuju i drugi nenamjenski mikroorganizmi. U radu je ispitana mikrobioloska kvaliteta uzoraka svježih i suhih oblika pekarskog kvasca razlicitih proizvođaca prisutnih na hrvatskom tržistu. Za izolaciju i identifikaciju mikrobne populacije u uzorcima pekarskog kvasca upotrijebljene su klasicne mikrobioloske metode, a mikrobni rast određen je brojanjem poraslih kolonija na selektivnim hranjivim podlogama. Rezultati su pokazali da su bakterije mlijecne kiseline (BMK) dominantni pridruženi mikroorganizmi pekarskom kvascu, prisutni u koncentraciji od 105 - 108 st/g. U uzorcima kvasca dokazani su i divlji kvasci i koliformne bakterije u koncentraciji od 103, odnosno 104st/g. Suhi pekarski kvasac imao je bolju mikrobiolosku kvalitetu buduci da u uzorcima nisu dokazane plijesni i bakterija Listeria monocytogenes. Salmonella sp. i Escherichia c...
Research Interests:
U ovom radu istražen je utjecaj dodatka razlicitih secera (glukoze, saharoze, laktoze i maltodekstrina ) na proces fermentacije kulenove seke proizvedene tradicionalnim postupkom. Uzorcima mesa i slanine, nadjeva te uzorcima kulenovih... more
U ovom radu istražen je utjecaj dodatka razlicitih secera (glukoze, saharoze, laktoze i maltodekstrina ) na proces fermentacije kulenove seke proizvedene tradicionalnim postupkom. Uzorcima mesa i slanine, nadjeva te uzorcima kulenovih seka tijekom procesa proizvodnje određena su fizikalno-kemijska svojstva, boja i tekstura, gubitak na masi (kalo) te je, u svrhu pracenja intenziteta i vremena trajanja procesa fermentacije, provedeno kontinuirano mjerenje pH vrijednosti. Proces fermentacije kulenove seke zapoceo je neposredno nakon pripreme nadjeva te je trajao približno 3 tjedna (uzorci s dodatkom 0, 8% maltodekstrina), odnosno oko 4 tjedna (referentni uzorak i uzorci s dodatkom 0, 8% laktoze, saharoze i glukoze), pri cemu se pH vrijednost s pocetnih 5, 5 – 5, 7 kontinuirano smanjivala do 5, 0 u uzorcima s maltodekstrinom, odnosno do vrijednosti 5, 3 – 5, 4 u ostalim uzorcima. Znacajne statisticke razlike (p 0, 05) utjecao na parametre profila teksture. Uzorak sa dodatkom maltodekstr...
Research Interests:
Oneciscenje namirnica mikotoksinima predstavlja ozbiljnu prijetnju ljudskome zdravlju, napose kada je rijec o namirnicama koje se ucestalo koriste u prehrani, a ujedno predstavljaju i znacajan izvor mikotoksina. Postupcima prerade hrane... more
Oneciscenje namirnica mikotoksinima predstavlja ozbiljnu prijetnju ljudskome zdravlju, napose kada je rijec o namirnicama koje se ucestalo koriste u prehrani, a ujedno predstavljaju i znacajan izvor mikotoksina. Postupcima prerade hrane može se postici smanjenje kolicine mikotoksina, njihova razgradnja, eliminacija ili transformacija u manje toksicne derivate, ali potpuno uklanjanje mikotoksina iz prehrambenog lanca putem prerade je tesko postici. Primjeni tehnika uklanjanja mikotoksina treba prethoditi utvrđivanje kemijskog sastava i toksicnosti nastalih produkta reakcije. U nedostatku potrebnih toksikoloskih podataka, za oblike mikotoksina koji nastaju tijekom prerade hrane, treba pretpostaviti da imaju istu razinu toksicnosti, istu biolosku raspoloživost i isti karcinogeni potencijal kao i izvorni spojevi. Prioritet za razvoj metoda smanjenja ili uklanjanja trebaju imati mikotoksini nepoželjnoga toksikoloskoga profila koji se ucestalo i u visokim koncentracijama pojavljuju u cest...
Research Interests:
Cheeses matured in skin sack is traditionally produced in several Mediterranean countries, which in Croatia has been retained in the territory of Dalmatian hinterland. The characteristic of this cheese is its piquant flavour and aroma, as... more
Cheeses matured in skin sack is traditionally produced in several Mediterranean countries, which in Croatia has been retained in the territory of Dalmatian hinterland. The characteristic of this cheese is its piquant flavour and aroma, as a consequence of ripening in anaerobic conditions in lamb skin. This type of cheese has been recognized and has its customers in the wider area of the Croatia, and it is an interesting touristic product. The major constraint is that the production of this type of cheese in Croatia has been reduced to sporadic production in several families that preserve the tradition of their ancestors and the produced quantities are insufficient to meet customers needs. In 2009, Dalmatian hinterland had 11 registered producers of this type of cheese, while there are currently only 2. A production and economic analysis was performed of the remaining producers in order to determine the production performance. Both family farms produce cheese from sheep milk, while t...
Research Interests:
Research Interests:
Mikotoksini učestalo kontaminiraju hranu i hranu za životinje, prvenstveno žitarice i proizvode na bazi žitarica. Citrinin je mikotoksin kojeg sintetiziraju pojedine plijesni iz roda Penicillium, Aspergillus i Monascus, među kojima je P.... more
Mikotoksini učestalo kontaminiraju hranu i hranu za životinje, prvenstveno žitarice i proizvode na bazi žitarica. Citrinin je mikotoksin kojeg sintetiziraju pojedine plijesni iz roda Penicillium, Aspergillus i Monascus, među kojima je P. citrinum njegov najznačajniji producent. S obzirom na nedostatnost podataka o razinama citrinina u žitaricama, u okviru ovog istraživanja analizirane se njegove koncentracije u kukuruzu (n=158) sa obiteljskih poljoprivrednih gospodarstava u Hrvatskoj tijekom petogodišnjeg razdoblja (2017.-2021.). Citrinin je detektiran u 25,3 % uzoraka kukuruza prikupljenih na području cijele Hrvatske tijekom petogodišnjeg razdoblja. Najveća prosječna koncentracija utvrđena je 2016. godine (162,9±162,0 µg/kg) te 2020. godine (154,9±358,8 µg/kg), a najveća koncentracija od 968,6 µg/kg određena je u 2020. godini u uzorku kukuruza uzorkovanom na području južne regije. S obzirom na utvrđenu značajniju kontaminaciju pojedinih uzoraka, može se zaključiti o nužnosti sustav...
Research Interests:
Tijekom posljednjeg desetljeća znanstven- ici sve više ukazuju na globalno zagrijavanje, dovodeći klimatske promjene u poveznicu s novom strukturom vrsta plijesni producenata mikotoksina po geografskim područjima svi- jeta.... more
Tijekom posljednjeg desetljeća znanstven- ici sve više ukazuju na globalno zagrijavanje, dovodeći klimatske promjene u poveznicu s novom strukturom vrsta plijesni producenata mikotoksina po geografskim područjima svi- jeta. Izraženije klimatske promjene mogu u budućnosti izmijeniti otpornost domaćina i interakciju domaćin-patogen te imati znatan utjecaj na razvoj toksikogenih plijesni i produk- ciju mikotoksina kao njihovih sekundarnih metabolita. Novonastala klimatološka situ- acija izaziva sve veću pozornost i zahtijeva nove dijagnostičke alate, kao i nove spoznaje o biološkim karakteristikama poljoprivrednih kultura koje se uzgajaju i genetici toksikogenih plijesni. Zbog sve povoljnijih klimatskih uvjeta za rast Aspergillus flavus na području Europe, u narednom razdoblju postoji povećani rizik od onečišćenja žitarica izrazito toksičnim aflatok- sinima. Ujedno, profil mikotoksigenih vrsta Fusarium počinje se sve znatnije mijenjati, a posebno je zabrinjavajući ...
Research Interests:
Research Interests:
During ripening, the surface of dry traditional meat products (TMPs) becomes overgrown by fungi of the Penicillium spp., Aspergillus spp. and Eurotium spp. whose spores mostly come from the environment in which the ripening chambers are... more
During ripening, the surface of dry traditional meat products (TMPs) becomes overgrown by fungi of the Penicillium spp., Aspergillus spp. and Eurotium spp. whose spores mostly come from the environment in which the ripening chambers are placed. Certain fungi species is often responsible for the occurrence of toxic compounds termed the mycotoxins, among which of the outermost importance in connection with meat products are aflatoxin B1 (AFB1) and ochratoxin A (OTA). Besides, some other mycotoxins such as citrinin (CIT), cyclopiazonic acid (CPA) and sterigmatocystin (STC) can also be present, but their impact on the quality and safety of meat products, and therefore also on human health, has still not been fully clarified. As control and prevention of toxicogenic fungi growth are key factors to the prevention of mycotoxin presence in dry-cured TMPs, levels of mycotoxin contamination, mycotoxin-producing mould species and factors of relevance for mycotoxin production, such as climate, ...
Research Interests:
Research Interests:
Research Interests:
Research Interests:
Fungicides are the most common agents used in postharvest treatment of fruit and are the most effective against blue mould, primarily caused by Penicillium expansum. Alternatively, blue mould can be treated with antagonistic... more
Fungicides are the most common agents used in postharvest treatment of fruit and are the most effective against blue mould, primarily caused by Penicillium expansum. Alternatively, blue mould can be treated with antagonistic microorganisms naturally occurring on fruit, such as the bacterium Gluconobacter oxydans. The aim of this study was to establish the antifungal potential of the G. oxydans 1J strain isolated from apple surface against Penicillium expansum in culture and apple juice and to compare it with the efficiency of a reference strain G. oxydans ATCC 621H. The highest antifungal activity of G. oxydans 1J was observed between days 3 and 9 with no colony growth, while on day 12, P. expansum colony diameter was reduced to 42.3 % of the control diameter. Although G. oxydans 1J did not fully inhibit mould growth, it showed a high level of efficiency and completely prevented patulin accumulation in apple juice.
Research Interests:
Growth Inhibition of Aspergillus Ochraceus ZMPBF 318 and Penicillium Expansum ZMPBF 565 by Four Essential OilsFungi produce a large variety of extracellular proteins, organic acids, and other metabolites and can adapt to several... more
Growth Inhibition of Aspergillus Ochraceus ZMPBF 318 and Penicillium Expansum ZMPBF 565 by Four Essential OilsFungi produce a large variety of extracellular proteins, organic acids, and other metabolites and can adapt to several environmental conditions. Mycotoxin-producing moulds of the genera Aspergillus and Penicillium are common food contaminants. One of the natural ways to protect food from mould contamination is to use essential oils. In this study, we evaluated the effect of essential oils of cinnamon, lavender, rosemary, and sage at 1 % (v/v) concentration in yeast media inoculated with spores (final concentration 106 mL-1 media) of Aspergillus ochraceus ZMPBF 318 and Penicillium expansum ZMPBF 565, alone or in combination, on fungal biomass. Cinnamon showed the best inhibitory effect (100 %). Lavender oil best inhibited the growth of Aspergillus ochraceus (nearly 100 %), and was less successful with Penicillium expansum (having dropped to 57 % on day 28). With cultivation t...
Research Interests:
The aim of this study was to determine the effects of the essential oil of Thymus serpyllum L. and of its components thymol and total phenols (total phenolic content, TPC) extracted from the plant on the growth and mycotoxin production of... more
The aim of this study was to determine the effects of the essential oil of Thymus serpyllum L. and of its components thymol and total phenols (total phenolic content, TPC) extracted from the plant on the growth and mycotoxin production of Aspergillus ochraceus, A. carbonarius, and A. niger. Minimal inhibitory concentration (MIC) determined for the essential oil and thymol, and selected concentration of the TPC extract inhibited fungal growth and ochratoxin A biosynthesis by more than 60 %, depending on the conditions and duration of incubation with the fungi. Essential oil showed the strongest inhibitory effect which may have been related to the synergistic or cumulative effects of its components
Research Interests:
This study aims to determine the effects of the autochthonous probiotic bacteria Lactobacillus plantarum B (currently Lactiplantibacillus plantarum) and Lactococcus lactis subsp. lactis S1 on proteolysis during the ripening of Sir iz... more
This study aims to determine the effects of the autochthonous probiotic bacteria Lactobacillus plantarum B (currently Lactiplantibacillus plantarum) and Lactococcus lactis subsp. lactis S1 on proteolysis during the ripening of Sir iz mišine—a Croatian cheese which ripens in a lambskin sack. Sir iz mišine was produced in four different variants: (1) from raw milk without starter cultures, and from pasteurized milk with added (2) Lactococcus lactis ssp. lactis S1, (3) Lactobacillus plantarum B, or (4) a starter culture consisting of a mixture of Lactococcus lactis ssp. lactis S1 and Lactobacillus plantarum B (1:1). The addition of Lactobacillus plantarum B alone or in combination with Lactococcus lactis subsp. lactis S1 noticeably increased the alpha and beta indices because of the synergistic activity between the enzymes responsible for primary proteolysis and added autochthonous bacteria. Cheese produced from raw milk had the lowest (12.16%) content of WSN%TN. The highest WSN%TN con...
Research Interests:
Mikotoksini su sekundarni metaboliti niske molekulske mase koje sintetiziraju plijesni iz rodova Aspergillus, Penicillium i Fusarium te su česti kontaminanti raznovrsnih prehrambenih proizvoda. Kako bi se smanjio rast plijesni, a time i... more
Mikotoksini su sekundarni metaboliti niske molekulske mase koje sintetiziraju plijesni iz rodova Aspergillus, Penicillium i Fusarium te su česti kontaminanti raznovrsnih prehrambenih proizvoda. Kako bi se smanjio rast plijesni, a time i udio mikotoksina u namirnicama, koriste se razne fizikalne i kemijske metode. Posljednjih nekoliko godina ispituje se učinak bakterija mliječne kiseline (BMK) na sposobnost inhibicije rasta plijesni i njihova uloga u uklanjanju mikotoksina iz kontaminirane hrane. Zbog svojih, po zdravlje korisnih svojstava, bakterije mliječne kiseline predstavljaju izvrsno rješenje za tretiranje namirnica kontaminiranih mikotoksinima. Cilj ovog rada bio je ispitati i usporediti sposobnosti, živih, mrtvih i liofiliziranih stanica BMK na vezanje aflatoksina M1 (AFM1) u umjetno kontaminiranom mlijeku. Ovisno o korištenom soju, vremenu inkubacije i tretmanu, uspješnost vezanja AFM1 stanicama BMK iznosila je 23,73-94,49%. Liofilizirane stanice ispitivanih sojeva BMK manje...
Research Interests:
Mikotoksini su sekundarni metaboliti toksikotvornih plijesni te su česti kontaminanti raznih prehrambenih proizvoda. Pojava aflatoksina M1 (AFM1) u mlijeku, prijetnja je zdravlju potrošača, posebice maloj djeci te dovodi do ekonomskih... more
Mikotoksini su sekundarni metaboliti toksikotvornih plijesni te su česti kontaminanti raznih prehrambenih proizvoda. Pojava aflatoksina M1 (AFM1) u mlijeku, prijetnja je zdravlju potrošača, posebice maloj djeci te dovodi do ekonomskih gubitaka zbog zbrinjavanja kontaminiranog mlijeka. Metode uklanjanja i/ili redukcije mikotoksina koje se koriste u prehrambenoj industriji troše velike količine energije i kemijskih sredstava, stoga biološke metode sve više dobivaju na značaju zbog svoje netoksičnosti i ekološkog aspekta. Cilj ovog rada je bio odrediti količinu nevezanog AFM1 nakon uklanjanja kompleksa β-glukan-AFM1 pomoću Centricon 70 Plus, MWCO 100 kDa filtera. U radu je upotrijebljen komercijalni β-glukan dobiven iz zobi i β-glukan izoliran iz biomase kvasca. Rezultati istraživanja ukazuju da je nakon uklanjanja kompleksa β-glukan-AFM1 u uzorku mlijeka zaostalo 35% AFM1 u slučaju kada je β-glukan dobiven iz zobi, odnosno 36,4% AFM1 kada je β-glukan izoliran iz kvasca.
Research Interests:
The purpose of this research was to determine whether the cream cheese and cream that are produced in the traditional manner at home and are free to sale on Zagreb markets, meet microbiological requirements for foodstuffs (OG 46/94,... more
The purpose of this research was to determine whether the cream cheese and cream that are produced in the traditional manner at home and are free to sale on Zagreb markets, meet microbiological requirements for foodstuffs (OG 46/94, 20/01, 40/01). Particular attention is given to research of bacteria Listeria monocytogenes presence in these foods, because of its exceptional hazards to human health. It was found that a majority of 64 (53 %) from a total of 120 studied dairy products samples were contaminated with microbial pathogens, of which 16 % are waste in the cream cheese, and 37 % in cream samples. 39 samples of cheese and 50 samples of cream did not fulfil the conditions prescribed by the Croatian Guidelines, primarily due to the contamination with yeasts and moulds. In 10 cheese and cream samples where L. monocytogenes is proven by classical microbiological methods, PCR method confirmed L. monocytogenes in only one cream sample.
Potential probiotic strains from different origins have been tested for some specific physiological properties in order to evaluate their application potentialities. The phenotypic characterisations of examined lactic acid bacteria have... more
Potential probiotic strains from different origins have been tested for some specific physiological properties in order to evaluate their application potentialities. The phenotypic characterisations of examined lactic acid bacteria have done using the API tests and BIOLOG system. All of tested strains survive lyophilization process in skim milk at high population level. Lyophilised strains remained viable at all examined temperatures during 75 days of storage. Recovery of viable cells during storage in the phosphate buffer with glycerol was about 100 % at – 20 oC for all strains. Cells of L. acidophilus M92 rapidly died during storage at 4 and 15 oC, while cells of L. plantarum L4 and E. faecium L3 survive at the number of ca. 104 cells/ml. The potential probiotic strains have shown antagonistic activity against all tested gram-positive and gram-negative spoilage and pathogenic bacteria using 3 different methods (agar-spot test, agar-well diffusion method and in vitro competition test). The inhibition obtained by neutralised 5-fold concentrated supernatant of L. plantarum L4 may be result of bacteriocin activity of this strain.
Research Interests:
Intestinalni ekosustav je složena mreža interakcija prokariotskih (autohtona crijevna mikroflora) i eukariotskih stanica domacina (covjeka ili životinje). Crijevna mikroflora iskazuje jak utjecaj na aktivnost limfaticnog tkiva probavnog... more
Intestinalni ekosustav je složena mreža interakcija prokariotskih (autohtona crijevna mikroflora) i eukariotskih stanica domacina (covjeka ili životinje). Crijevna mikroflora iskazuje jak utjecaj na aktivnost limfaticnog tkiva probavnog sustava (eng. GALT - Gut-Associated Lymphoid Tissue) i razvoj regulacijskih mehanizama ukljucenih u održavanje i aktivaciju imunoloskog statusa domacina i može varirati ovisno o stabilnoj ili poremecenoj ravnoteži crijevne mikroflore. Treba imati na umu da je gastrointestinalni sustav najveci "imunoloski organ" ljudskog organizma, jer povrsina tankog i debelog crijeva iznosi oko 300 m2, a masa crijevne mikroflore zdravog organizma covjeka iznosi oko 1, 2 kg. Utjecaj konvencionalne prehrane kao i dodataka hrani na sastav intestinalne mikroflore je dokazan brojnim istraživanjima. Uloga crijevne mikroflore u zdravlju ocituje se ne samo kroz modulaciju imunoloskog odogovora, nego i kroz prevenciju karcinogeneze. Rezultati istraživanja primjene probiotika i prebiotika u svrhu uspostavljanja i održavanja ravnoteže crijevne mikroflore, dodatno su doprinjela razumijevanju kompleksnog intestinalnog ekosustava i interakcije crijevne mikroflore, prehrane i imuniteta kao pokazatelja dobrog zdravlja.
Research Interests:
Research Interests:
Research Interests:
Potential probiotic strains from different origins have been tested for some specific physiological properties in order to evaluate their application potentialities. The phenotypic characterisation of examined lactic acid bacteria have... more
Potential probiotic strains from different origins have been tested for some specific physiological properties in order to evaluate their application potentialities. The phenotypic characterisation of examined lactic acid bacteria have done using the API tests and BIOLOG system. All of tested strains survive lyophilization process in skim milk at high population level. Lyophilised strains remained viable at all examined temperatures during 75 days of storage. Recovery of viable cells during storage in the phosphate buffer with glycerol was about 100 % at – 20 oC for all strains. Cells of L. acidophilus M92 rapidly died during storage at 4 and 15 oC, while cells of L. plantarum L4 and E. faecium L3 survive at the number of ca. 104 cells/ml. The potential probiotic strains have shown antagonistic activity against all tested gram-positive and gram-negative spoilage and pathogenic bacteria using 3 different methods (agar-spot test, agar-well diffusion method and in vitro competition test). The inhibition obtained by neutralised 5-fold concentrated supernatant of L. plantarum L4 may be result of bacteriocin activity of this strain.
Research Interests:
The synbiotic effect of the oral treatment of Swiss albino mice with milk-based diets supplemented with Lactobacillus helveticus M92 and various kinds of prebiotics was investigated. Survival, competition, adhesion and colonization, as... more
The synbiotic effect of the oral treatment of Swiss albino mice with milk-based diets supplemented with Lactobacillus helveticus M92 and various kinds of prebiotics was investigated. Survival, competition, adhesion and colonization, as well as, immunomodulating capability of Lb. helveticus M92, in synbiotic combination, in the gastrointestinal tract (GIT) of mice, were monitored. After the mice were fed with synbiotics, the lactic acid bacteria (LAB) counts in faeces were increased and reduction of enterobacteria and sulphite-reducing clostridia was observed. Similar results were obtained in homogenates of small and large intestine of mice on the 1st and 14th day, after feeding with synbiotics. After the mice were orally given viable Lb. helveticus M92 cells, alone or in combination with prebiotic, the concentration of faecal SIgA and total serum IgA antibodies from all immunized mice were higher compared with the control. The specific humoral immune response was not evoked after oral administration, therefore their synbiotic application is suitable. Among inulin, lactulose and raffinose, Lb. helveticus M92 in combination with inulin, has shown the best synbiotic effect on intestinal and faecal microflora and immune system of mice.
Research Interests:
Research Interests:
Research Interests:
Adhesion to intestinal epithelial cells is an important prerequisite for colonization of probiotic strains in the gastrointestinal tract, preventing their immediate elimination by peristalsis and providing a competitive advantage in this... more
Adhesion to intestinal epithelial cells is an important prerequisite for colonization of probiotic strains in the gastrointestinal tract, preventing their immediate elimination by peristalsis and providing a competitive advantage in this ecosystem. The aim of this work was to investigate adhesiveness of Lactobacillus acidophilus M92 to mouse ileal epithelial cells in vitro. Subsequently, adhesiveness and survival in vivo was monitored by measuring the faecal and intestinal level of L. acidophilus M92 after oral administration of this strain on mice. During the feeding of mice with L. acidophilus M92 with daily dose of 2.2x10on10 cells, the number of lactobacilli in faeces was increased and reduction of enterobacteria and sulphite-reducing clostridia was observed. The similar results were obtained in homogenates of small and large intestine of mice in the 1st and 14th day after feeding with L. acidophilus M92, which pointed out adherence and colonisation ability of examined strain. These results confirmed adhesiveness ability of L. acidophilus M92 to mouse ileal epithelial cells obtained in vitro. This investigation has shown that L. acidophilus M92 has ability to establish in the human gastrointestinal tract alters the composition of the intestinal microflora and faeces, what is an important determinant in the choice of probiotic strains.
Research Interests:
Research Interests:
The protective effects of the oral treatment with Lactobacillus helveticus M92 in an intragastric challenge by Salmonella enterica serovar Typhimurium were investigated. Mice were fed with milk-based diets supplemented with L. helveticus... more
The protective effects of the oral treatment with Lactobacillus helveticus M92 in an intragastric challenge by Salmonella enterica serovar Typhimurium were investigated. Mice were fed with milk-based diets supplemented with L. helveticus M92, for seven days prior to and following oral challenge with S. Typhimurium. Survival, competition, adhesion and colonization of L. helveticus M92 in combination with S. Typhimurium were monitored in the gastrointestinal tract of mice, as well as their immunomodulating capability. After feeding of mice with L. helveticus M92 the total number of lactic acid bacteria in faeces was increased, contrary the reduction of total number of enterobacteria was observed, compared to non-probiotic-fed mice (mice fed with S. Typhimurium). These results were in accordance with results obtained in homogenates of small and large mice intestine 7th day after feeding with L. helveticus M92. Following the oral immunization of mice, with a daily dose of 1 x 1011 viable L. helveticus M92 cells, the concentration of serum anti-S. Typhimurium IgA antibodies from all immunized mice was significantly higher compared to non-probiotic-fed mice i.e. mice fed with S. Typhimurium and to the control group of mice. Interestingly, results showed that, after the challenge, L. helveticus M92 – fed mice exhibited lower cumulative morbidity and bacterial translocation rates, compared to non-probiotic-fed mice. These results demonstrate that L. helveticus M92 can reduce the severity of infection due to the pathogen S. Typhimurium, and suggest that the reduction may be associated with enhanced immune protection conferred by the probiotic.
Research Interests:
The increasing application of probiotic cultures in food products underscores the need to properly identify and distinguish these beneficial bacteria among originally presented microbial population. Probiotic strain Lactobacillus... more
The increasing application of probiotic cultures in food products underscores the need to properly identify and distinguish these beneficial bacteria among originally presented microbial population. Probiotic strain Lactobacillus plantarum L4 and Leuconostoc mesenteroides LMG 7954 were introduced as starter cultures in sauerkraut production for improvement of fermentation process and product quality. Lower biogenic amine content and shorter duration of fermentation were obtained in production of sauerkraut with starter cultures. To check out the influence of starter culture strains, ten randomly chosen lactic acid bacteria isolates from controlled fermentation were genotyped by pulsed-field gel electrophoresis (PFGE), together with six reference strains for comparison. Electrophoretic karyotype of NotI-digested genomic DNA revealed 6 isolates as Lactobacillus plantarum, one was identified as Leuconostoc mesenteroides and one as possible Lactobacillus rhamnosus. The two remained isolates showed specific karyotype that could not be identified after comparison with reference strains. Results obtained by PFGE were confirmed by SDS-PAGE of whole cell proteins. Further phenotypic characterization of all strains examined was evaluated by studying biochemical characteristics (API carbohydrate fermentation patterns and acidifying activities) of technological interest. The results indicated that electrophoretic karyotype determined by PFGE allowed to confirm the identity of starter strains between other isolates and can be employed to study the genetic diversity of lactic acid bacteria from an ecosystem like that found in fermenting vegetables.
Research Interests:
Probiotic bacteria and its components can act on the immune system and increase the body's resistance to infections, cancer and allergy by enhancing the immune response in the host. Therefore, the effect of probiotic strain... more
Probiotic bacteria and its components can act on the immune system and increase the body's resistance to infections, cancer and allergy by enhancing the immune response in the host. Therefore, the effect of probiotic strain Lactobacillus acidophilus M92 on the specific and total humoral immune response in Swiss albino mice was studied. Mice were immunized intraperitoneally or orally with a dose of 2· 10 on the power of 10 viable or non-viable cells of L. acidophilus M92. The blood samples were collected 4th, 8 th, 10 th, 14 th, 17 th and 21 th day after first immunization. Sera samples from all groups of mice were tested for total and specific anti-lactobacilli IgA, IgG and IgM antibodies with ELISA assay. Irrespective of the way of immunization or bacterial cell preparation, the concentration of total serum IgA, IgG and IgM antibodies from all groups were significantly higher in addition to control groups. The higher levels of specific anti-lactobacilli IgG and IgM antibodies after intraperitoneal (i.p.) than after oral immunization were detected in mice immunized with viable or non-viable cells of L. acidophilus M92. It didn't evoke the specific humoral immune response after oral application and is as such suitable for probiotic application. The results have shown that L. acidophilus M92 has immunomodulatory activity and could be able to protect against various diseases.
Research Interests:
S-layer proteins form a crystalline layer around the cells of several Lactobacillus species, and it has been proposed that these proteins are involved in cell protection, adherence, and surface recognition, which are important... more
S-layer proteins form a crystalline layer around the cells of several Lactobacillus species, and it has been proposed that these proteins are involved in cell protection, adherence, and surface recognition, which are important characteristics for probiotic strains. The surface proteins of probiotic strain L. acidophilus M92 were examined for the presence of S-layer, and as a standard strain was used L. acidophilus ATCC 4356 which possessed S-protein of 43 kD. Sodium dodecyl sulphate polyacrylamide gel electrophoresis (SDS-PAGE) of cell surface proteins revealed the presence of potential surface layer (S-layer) proteins, approximated at 45 kDa in L. acidophilus M92. Southern blot with pBK1 plasmid conteing slpA gene gave a positive signal, suggesting that L. acidophilus M92 has a slpA gene coding for the S-layer proteins. S-layer proteins of this strain are present during all phases of growth. The S-layer reappeared when treated cells were allowed to grow again. Removal of the S-layer proteins reduced adhesion of L. acidophilus M92 to mouse ileal epithelial cells. Furthermore, the viability of cells without S-layer were reduced in simulated gastric juice at low pH range (2, 2· 5, 3) and simulated pancreatic juice with bile salts (1· 5 g l-1 and 3 g l-1). S-layer proteins of L. acidophilus M92 were resistant to pepsin and pancreatin, in contrast, the treatment with proteinase K led to a significant proteolysis of the S-layer proteins. These results demonstrated functional role of S-layer ; it is responsible for adhesiveness of Lactobacillus acidophilus M92 to mouse ileal epithelial cells and has a protective role for this strain.
Research Interests:
The human gastrointestinal tract constitutes a complex microbial ecosystem comprising 400 different species of bacteria. These organisms and their metabolic activities can have both positive and negative impact on human health. The... more
The human gastrointestinal tract constitutes a complex microbial ecosystem comprising 400 different species of bacteria. These organisms and their metabolic activities can have both positive and negative impact on human health. The maintenance of a community of bacteria which contains a predominance of beneficial species (lactic acid bacteria) and minimal putrefactive processes is believed to be important for maintaining intestinal health. Hence, probiotics (live microorganisms such as lactic acid bacteria that are added to food and that possess health-promoting properties) and prebiotics (non-digestible food ingredients that stimulate the lactic acid bacteria present in the colon) may be considered as driving forces of the functional foods' production. Such synbiotics (probiotics and prebiotics) offer a realistic way of using biological preparations in the prevention of gastrointestinal diseases in humans and animals. Three strains of lactic acid bacteria were selected for probiotic activity according to complex scientific in vitro selection criteria: Lactobacillus acidophilus M92, Lactobacillus plantarum L4 and Enterococcus faecium L3. On the basis of probiotic concept, implantation of the viable cells in the gastrointestinal tract and stimulation of metabolic activities of selected potential probiotic strains with prebiotic substrates can lead to enhanced effect, termed the synbiotic effect. It is a general goal of actual scientific project "Role of lactic acid bacteria in synbiotic effect - 0058009".
Research Interests:
Lactobacilli are major microorganisms of the normal human microbiota, and the determination of the mechanisms through which they colonize the intestinal tract may provide important insight into how the normal microbiota is maintained as... more
Lactobacilli are major microorganisms of the normal human microbiota, and the determination of the mechanisms through which they colonize the intestinal tract may provide important insight into how the normal microbiota is maintained as well as provide a basis for the selection of probiotic strains. The ability of probiotic bacteria to adhere to the intestinal epithelium play an important role in colonization of the gastrointestinal tract, preventing their elimination by peristalsis and providing a competitive advantage in this ecosystem. To identify bacterial traits related to adhesion the probiotic strain L. acidophilus M92 was examined for autoaggregation ability and cell surface hydrophobicity. L. acidophilus M92 exhibits a strong autoaggregating phenotype and also coaggregation with some pathogen microorganisms that may form a barrier that prevents their colonization. The examined probiotic strain manifests a high degree of hydrophobicity determined by microbial adhesion to hydrocarbons. Aggregation and hydrophobicity were abolished upon exposure of the cells to pronase and pepsin, which suggest the possible role of cell surface proteins in the aggregation phenotype. SDS-PAGE of cell surface proteins revealed the presence of potential surface (S-) layer proteins, approximated at 45 kDa, in L. acidophilus M92. The relationship between autoaggregation and adhesion ability to intestinal tissue was investigated by observing the adhesivity of L. acidophilus M92 to porcine ileal epithelial cells. Removal of the S-layer proteins by extraction with 5 M LiCl reduced autoaggregation and in vitro adhesion of this strain.
Research Interests:
Changes in physicochemical, colour, textural, microbiological and sensory attributes occurring during the processing of Horse Salami and established on manufacturing days 0, 7, 14, 21, 28, 42, 60, 90 were studied. Significant changes... more
Changes in physicochemical, colour, textural, microbiological and sensory attributes occurring during the processing of Horse Salami and established on manufacturing days 0, 7, 14, 21, 28, 42, 60, 90 were studied. Significant changes (P<0.05) in physicochemical parameters attributable to moisture loss, as well as changes in colour and textural properties were observed during the fermentation and ripening stage. Proteolysis and lipolysis, coming as a result of endogenous enzymatic activity and high lactic acid bacteria and staphylococci counts, contributed to specific organoleptic properties of the final product. Sensorial profiling showed a significant (P<0.05) acid taste, lactic acid odour and flavour intensity, and low fat/lean ratio and smokiness and saltiness values. Final Horse Salami products were microbiologically safe, the dominant microbial population thereby being Lactobacillus plantarum, Lactococcus lactis ssp. lactis, Enterococcus faecium and Staphylococcus xylosus.
Research Interests:
Svrha ovog rada bila je izolirati autohtonu mikrobnu populaciju iz uzoraka slavonskih kulena proizvedenih na tradicionalan nacin u seoskim domacinstvima. Autohtona mikrobna populacija izvor je sojeva za razvoj starter kultura koje ce,... more
Svrha ovog rada bila je izolirati autohtonu mikrobnu populaciju iz uzoraka slavonskih kulena proizvedenih na tradicionalan nacin u seoskim domacinstvima. Autohtona mikrobna populacija izvor je sojeva za razvoj starter kultura koje ce, između ostalog, utjecati na aromu i teksturu određenog tradicionalnog mesnog proizvoda. Dominantna mikrobna populacija sastojala se od bakterija mlijecne kiseline (BMK) i to : Lactobacillus plantarum u dva uzorka, Lactobacillus delbrueckii u dva uzorka, te Leuconostoc mesenteroides i Lactobacillus acidophilus u po jednom uzorku kulena. Također, su prevladavale i bakterije iz roda Staphylococcus, tipicni predstavnici starter kultura za meso, i to: S. xylosus, S. warneri, S. lentus i S. auricularis u broju od 3, 30-5, 56 log10 CFU/g uzorka. U dva uzorka kulena izolirani su i kvasci, predstavnici starter kultura za meso: Candida famata. Kvasci su izolirani s povrsine ovoja i iz sredine kulena u broju 3, 48 - 6, 48 log10 CFU/g. Sa povrsine 4 od 6 analizira...
Research Interests:
Production of functional food supplemented with probiotic bifidobacteria is of growing interest because of the health-promoting effects in humans. In this study a novel probiotic product was prepared: cereal flakes enriched with inulin... more
Production of functional food supplemented with probiotic bifidobacteria is of growing interest because of the health-promoting effects in humans. In this study a novel probiotic product was prepared: cereal flakes enriched with inulin and a lyophilized probiotic culture of Bifidobacterium animalis subsp. lactis BB-12, intended to be used as an infant formula. The influence of this food matrix on probiotic properties of B. animalis subsp. lactis BB-12 was examined. The tolerance to simulated gastric and small intestinal juices was much higher when the B. animalis subsp. lactis BB-12 probiotic culture was applied in combination with cereal flakes, inulin and skim milk with respect to the use of the pure lyophilized probiotic culture. Bile salt resistance and bile salt hydrolase activity (BSH) of B. animalis subsp. lactis BB-12 was also monitored in vitro. Furthermore, the influence of cereal flakes and inulin on the functional probiotic properties of B. animalis subsp. lactis BB-12 w...
Research Interests:
Prirucnik za vježbe iz mikrobiologije osim studentima, namijenjen je i onima koji rade u pojedinim mikrobioloskim laboratorijima.