In-situ inhibition of Listeria monocytogenes by lactic acid bacteria

Svrha ovog rada bila je provjeriti da li izolirani soj bakterija mliječne kiseline Lactobacillus plantarum A1 pokazuje antilisterijska svojstva u svježem sirovom mlijeku. Listeria monocytogenes je odavna prepoznata kao humani patogen, ali je tek ranih 80-tih godina prošlog stoljeća uočeno da je kontaminirana hrana glavni put prijenosa te bakterije iz okoliša u ljude. S obzirom da je za listeriju još uvijek nepoznata infekcijska doza, propisani su vrlo strogi standardi za ovu bakteriju – 0/25 g uzorka. U današnje vrijeme, sve je veći trend zaštite i konzerviranja hrane na prirodan način, te je sve više potrošača zainteresirano za što prirodnije proizvode radi poboljšanja zdravlja, primjenom bioprotektivnih kultura, kao što su bakterije mliječne kiseline (BMK), koje svojim rastom i proizvodnjom metabolita (organskih kiselina i bakteriocina) sprječavaju kvarenje i produžuju vijek hrane, a za koje je dokazano da imaju antimikrobni učinak na patogene mikroorganizme. U mlijeku koje je bilo podvrgnuto vremensko-temperaturnom režimu proizvodnje tradicionalnog svježeg sira, kultura BMK inhibirala je rast bakterije Listeria monocytogenes u rasponu od 40 do 50 % u ovisnosti o vremenu inkubacije.The purpose of this study was to verify whether the isolated strain of lactic acid bacteria Lactobacillus plantarum A1 shows antilisterial properties in fresh raw milk. Listeria monocytogenes has long been recognized as a human pathogen, but only the early 1980s of the past century it was noticed that contaminated food was a main way of bacterial transmission from the environment to humans. Given that the listeria was still unknown infectious doses prescribed are very strict standards for the bacteria – 0/25 g sample. Nowadays, an increasing trend in the protection and preservation of food in a natural way, and more consumers are interested in the natural products to improve health, using bioprotective culture, such as lactic acid bacteria (LAB), which by their growth and production of metabolites (organic acids and bacteriocins) to prevent spoilage and extend the life of food, which has been shown to have antimicrobial effect on pathogenic microorganisms. The milk that was subjected to time-temperature regime of the traditional production of cheese, the culture of LAB inhibited the growth of Listeria monocytogenes in a range of 40 to 50 % depending on the incubation time