title: Antimicrobial activity of acid-hydrolyzed Citrus unshiu peel extract in milk.
abstract: Citrus fruit (Citrus unshiu) peels were extracted with hot water and then acid-hydrolyzed using hydrochloric acid. Antimicrobial activities of acid-hydrolyzed Citrus unshiu peel extract were evaluated against pathogenic bacteria, including Bacillus cereus, Staphylococcus aureus, and Listeria monocytogenes. Antilisterial effect was also determined by adding extracts at 1, 2, and 4% to whole, low-fat, and skim milk. The cell numbers of B. cereus, Staph. aureus, and L. monocytogenes cultures treated with acid-hydrolyzed extract for 12h at 35°C were reduced from about 8log cfu/mL to <1log cfu/mL. Bacillus cereus was more sensitive to acid-hydrolyzed Citrus unshiu peel extract than were the other bacteria. The addition of 4% acid-hydrolyzed Citrus unshiu extracts to all types of milk inhibited the growth of L. monocytogenes within 1d of storage at 4°C. The results indicated that Citrus unshiu peel extracts, after acid hydrolysis, effectively inhibited the growth of pathogenic bacteria. These findings indicate that acid hydrolysis of Citrus unshiu peel facilitates its use as a natural antimicrobial agent for food products.
authors.affiliation: Division of Animal Life Science, Konkuk University, Seoul 143-701, Korea.
authors.forename: Keun Young
authors.initials: KY
authors.lastname: Min
authors.affiliation: Department of Food Bioengineering, Jeju National University, Jeju 690-756, Korea.
authors.forename: Hyun Jung
authors.initials: HJ
authors.lastname: Kim
authors.affiliation: Division of Animal Life Science, Konkuk University, Seoul 143-701, Korea.
authors.forename: Kyoung Ah
authors.initials: KA
authors.lastname: Lee
authors.affiliation: Bio/Molecular Informatics Center, Konkuk University, Seoul 143-701, Korea.
authors.forename: Kee-Tae
authors.initials: KT
authors.lastname: Kim
authors.affiliation: Division of Animal Life Science, Konkuk University, Seoul 143-701, Korea; Bio/Molecular Informatics Center, Konkuk University, Seoul 143-701, Korea. Electronic address: hdpaik@konkuk.ac.kr.
authors.forename: Hyun-Dong
authors.initials: HD
authors.lastname: Paik
mesh_terms: D000818:Animals; D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D001409:Bacillus cereus / Q000187:drug effects*; D002957:Citrus / Q000737:chemistry*; D005520:Food Preservatives / Q000494:pharmacology*; D008089:Listeria monocytogenes / Q000187:drug effects*; D008892:Milk / Q000737:chemistry / Q000382:microbiology*; D010936:Plant Extracts / Q000737:chemistry; D013211:Staphylococcus aureus / Q000187:drug effects*
chemical_list: D000900:Anti-Bacterial Agents; D005520:Food Preservatives; D010936:Plant Extracts
keywords: Citrus unshiu peel; acid hydrolysis; antimicrobial effect; flavonoid; pathogen