Prospecting of culturable acetic acid bacteria from fermented fruits
The flavored vinegars made from wines and fruit are y highlighted in the food gastronomy market. However it is not easy to have a good starter. It is easy to found acetic acid bacteria (AAB) in the natural fermentation of fruits where they are mixed with yeasts. A medium was adapted have only AAB. For test this medium overripe fruits were fermentedby 3 days at room temperature and sampled as inoculum. Bacteria presenting AAB characteristics were identified in microscope. Samples with0.5mlwere placed into Petri dishes containing a modified Frateurmediumcomposed of agar, yeast extract, alcohol, and calcium carbonate. As fungistaticswere tested the gentian violet (1% methylrosanilinium chloride) and nystatin water solution (105 IU) both used at 0.5/1.0/1.5mlon 20mlof the mediumdirectly placed into sterile plates. Petri dishes were incubated at 25°C for five days and AAB colonies recognized by forming a halo. The data showed that only nystatin at dose 1.0 mlcontrolled the wild yeasts growth. Biochemical assays (Gramstaining, oxidase, catalase, indol and H2S formation)confirmed the genus Acetobacter. The data proving that the combination of Frateur medium with 1.0 mlof water solution of nystatin 105 IU)may be a good option for isolating AAB from fermenting fruit.