Estratti di origine vegetale: studi in vitro dell’attività antibatterica e analisi di shelf-life in burger a base di trota

In recent years, consumer demand for food without synthetic additives has significantly increased. Indeed, food industry is researching plant extracts as source of bioactive compounds that could represent a valid alternative to synthetic additives, which are increasingly associated with allergies and disorders in the gastrointestinal tract. This research project, aimed to evaluate the antibacterial effect of two different types of vegetable extracts obtained from oil vegetation waters (OMWs) and a Satureja L.. The antibacterial effect, associated to the phenolic concentration of the vegetative extract, was evaluated in vitro, with a microtiter assay, in order to assess the Minimum inhibitory concentration (MIC) and the Minimum bactericidal concentration (MBC) on some gram positive and negative bacteria (Listeria innocua, Listeria monocytogenes, Staphylococcus aureus, Staphylococcus xylosus and Escherichia coli). The antibacterial effect was also tested in a food model: fish-burger obtained from rainbow trout. In particular, it was performed a shelf-life analysis, to evaluate the effect of the OMWs extract and Satureja L. in fish burger according the growth of some spoilage microorganisms (Pseudomonas spp. and bacteria H2S producer). Moreover, during the shelf-life analysis, some bacterial colonies were isolated in order to perform a molecular analysis to check the putative bacterial strains. Vegetative antimicrobials may be used in food to improve the safety product, or to extend the shelf-life of food, by inhibiting or inactivating spoilage microorganism. However, for this purpose, many factors have to be considered, as the efficacy against target microorganisms in the food matrix, the effect of the compounds on sensory properties of food, the cost of the antimicrobial and labelling consideration.