Preparation of Fermented Citrus Peels Extracts for Their Antimicrobial Activity against Campylobacter jejuni

Abstract

Jeju citrus, which contains an abundance of calcium and vitamin, was used to develop fermented citrus peel extract. A total of seven probiotic strains were applied to tangerine dermis to select the best growing bacteria in citrus peel extracts. B. longum, B. bifidum, and L. mesenteroides were found to grow best in citrus peel extract culture containing glucose, yeast extracts, peptone, and potassium phosphate. Citrus peel extract culture consisting of 1% yeast extract, 5% peptone, and 0.1% phosphate was the best environment for growth of probiotics. The pH, acidity, and viable cell numbers of these fermented extracts were measured. The initial pH level of fermented extracts with nutrients was 5.25 and dropped rapidly to 3.39 after 72 hours of fermentation. The acidity of fermented extracts increased to 4.08 % after 72 hours of fermentation, and the viable cell number in fermented extracts after refrigeration for 2 weeks was . The antimicrobial activity of citrus peel fermented extracts against Campylobacter jejuni was determined, and concentrations more than 25,000 ppm showed antimicrobial activity.