Evaluation of antimicrobial activity of green tea kombucha at two fermentation time points against Alicyclobacillus spp.

Abstract

Natural antimicrobial is an effective alternative for control Alicyclobacillus spp., known to cause spoilage in fruit juices. Because of this, in this study, evaluated the antibacterial activity of green tea fermented at 7 and 14 days with Kombucha (K07 and K14). The species used were Alicycobacillus acidoterrestris 0244T, Alicyclobacillus herbarius 0246T, Alicyclobacillus acidiphilus 0247T, Alicyclobacillus cycloheptanicus 0297T, Alicyclobacillus hesperidum 0298T. Minimum Inhibitory Concentration (MIC) and Minimum Bactericidal Concentration (MBC) was performed against Alicyclobacillus. At 50% concentration of green tea, 1,563% K07 and 0.195% K14, there was a bacteriostatic effect (MIC) for all strains studied. While the minimum bactericidal concentration ranged from <50% to 12.5% for all isolates. Kombucha application on 1 × , 4 × , 8 × of MICs in contaminated orange juice with A. acidoterrestris (6.5 log CFU/mL) reduced population by up to 4 logs. Through the analysis of DPPH, FRAP and ABTS it was possible to verify that fermented beverages have good antioxidant activity. The characterization of the samples using the UHPLC-HRMS analysis method showed that fermentation of green tea with Kombucha increased the number of compounds in beverages. Scanning electron microscopy (SEM) was able to show damage to cells treated with fermented Kombucha at different times.