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Mliječni proizvodi se osim po hranjivosti i blagotvornom učinku na zdravlje potrošača, izdvajaju kao dobar izvor bakterija mliječne kiseline (BMK) s mogućom primjenom u proizvodnji novih starter kultura i probiotičkih pripravaka. Poznato je da BMK posjeduju dugu tradiciju primjene u fermentacijskim procesima kojim se dobivaju namirnice blagog okusa, ugodne arome, visoke nutritivne vrijednosti i funkcionalnih svojstava. Korištenjem BMK iz spomenutih sirovina, osigurava se njihova bolja prilagodba tehnološkom procesu i veća učinkovitost proizvodnje fermentiranih mliječnih proizvoda. Kako bi njihova primjena uopće bila moguća, potrebno je zadovoljiti stroge selekcijske kriterije koji osiguravaju izbor soja s dobrim tehnološkim i funkcionalnim karakteristikama te sigurnog za upotrebu. In addition to their nutritional value and beneficial effect on consumer health, dairy products stand out as an adequate source of lactic acid bacteria (LAB) with possible application in the production of starter cultures and probiotics. It is known that LAB has a long tradition of application in fermentation processes where they produce food with a mild taste, pleasant aroma, high nutritional value and functional properties. By using LAB from the mentioned raw materials, their better adaptation to the technological process and greater efficiency of production of fermented dairy products is ensured. In order for their application to be possible at all, it is necessary to meet strict selection criteria that ensure the selection of strains with good technological and functional properties and safe to use.

Bacterial adhesion to fish surface and survival in gastrointestinal tract are essential characteristics in order to select probiotic candidate for aquaculture products. In our previous research we isolated Lactobacillus plantarum O1 from the gut of sea bream (Sparus aurata) and characterized it as plantaricin producer and bioprotective culture. This strain was successfully used for biopreservation of fresh sea bass (Dichentrarchus labrax), mussels (Mytilus galloprovincialis) and oysters (Ostrea edulis) with extension of shelf life to ten days and thirteen days, respectively. In order to characterize it as potential fish probiotic, L. plantarum O1 was examined for in vitro adhesion to sea bass mucus, survival in 10% sea bass bile and gastric contents as well as survival in sea water and hemolytic activity. Results showed good adhesion capacity to fish surface mucus as well as high survival rate in 10% bile and stomach content. L. plantarum O1 also withstood sea water environment and didn’t lyse red blood cells. These results suggest that L. plantarum O1 has potential application as fish probiotic and further studies are required to evaluate these properties in aquatic animals.

Bakterije mliječne kiseline se zbog svojih poželjnih karakteristika i sinteze korisnih metabolita, intenzivno koriste kao starter kulture u različitim proizvodnim procesima, a ponajprije u proizvodnji fermentirane hrane. Kako bi neki bakterijski soj postao starter kultura potrebno je provesti niz istraživanja i dokazati da je ta kultura sigurna za primjenu, tehnološki učinkovita, a njena primjena prihvatljiva s ekonomskog stajališta. Određivanje optimalnih parametara za uzgoj bakterijskih sojeva je od iznimne važnosti za njihovo buduće korištenje u proizvodnim procesima te je stoga cilj ovog rada bio odrediti optimalnu temperaturu i optimalnu pH vrijednost autohtone mikrobne populacije bakterija mliječne kiseline izoliranih iz riba i školjkaša Jadranskog mora. Utvrđeno je da je za rast sojeva Lactobacillus plantarum D1 i Lactobacillus plantarum K4 optimalna temperatura 28°C a za Lactobacillus plantarum O1, Lactobacillus helveticus O9 i Leuconostoc mesenteroides L4A 37°C. Optimalna pH vrijednost za L. plantarum D1, L. plantarum K4, L. helveticus O9 i L. mesenteroides iznosi 6.0, dok L. plantarum O1 najbolje preživljavljava pri pH 4.0. The lactic acid bacteria, due to their desirable characteristics and synthesis of useful metabolites, are intensely used as starter cultures in different production processes, and above all in fermented food production. In order for some bacterial strain to become a starter culture, it is necessary to conduct a series of researches and prove that this culture is safe for use, technologically efficient and its application is acceptable from an economic point of view. Determination of optimal parameters for cultivation of bacterial strains is very important for their future use in production processes and therefore the purpose of this paper was determine the optimal temperature and optimum pH value of the autochtonus microbal population of lactic acid bacteria isolated from fish and shelfish. It was found that optimal temperature for growth of Lactobacillus plantarum D1 and Lactobacillus plantarum K4 is 28 °C and for Lactobacillus plantarum O1, Lactobacillus helveticus O9 and Leuconostoc mesenteroides L4A is 37 °C. The optimal pH value for Lactobacillus plantarum D1, Lactobacillus plantarum K4, Lactobacillus helveticus O9 and Leuconostoc mesenteroides is 6.0, while L. plantarum O1 survives at pH 4.0.