Antibacterial effect and mechanism of anthocyanin rich Chinese wild blueberry extract on various foodborne pathogens

Authors: SUN, XIAOHONG - Shanghai Ocean University; ZHOU, TONG-TONG - Shanghai Ocean University; WEI, CAI-HONG - Shanghai Ocean University; LAN, WEI-QING - Shanghai Ocean University; ZHAO, YONG - Shanghai Ocean University; PAN, YING-JIE - Shanghai Ocean University; Wu, Vivian

Submitted to: Food Control
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 7/6/2018
Publication Date: 7/11/2018
Citation: Sun, X., Zhou, T., Wei, C., Lan, W., Zhao, Y., Pan, Y., Wu, V.C. 2018. Antibacterial effect and mechanism of anthocyanin rich Chinese wild blueberry extract on various foodborne pathogens. Food Control. 94:155-161. https://doi.org/10.1016/j.foodcont.2018.07.012.
DOI: https://doi.org/10.1016/j.foodcont.2018.07.012

Interpretive Summary: It is important to control foodborne pathogens and prevent possible outbreaks. To minimize the use of chemical preservatives and antibiotics in agricultures while satisfying the consumer demands, it is important to explore effective alternative approaches such as use of natural food preservatives. Many investigations had been conducted to determine the content of blueberry extracts and showed that blueberry extracts, such as phenolic acids and flavonoids, have antimicrobial activity especially anthocyanins. This present study determined the minimum inhibitory/ bactericidal concentrations (MIC/MBC) and the antimicrobial activity of anthocyanins extracts from Chinese wild blueberries against L. monocytogenes, S. aureus, S. enteritidis and V. parahaemolyticus. The possible inhibitory mechanisms of anthocyanins from Chinese wild blueberries on four foodborne pathogens were also investigated. It was found that anthocyanins have significant antibacterial activity which damage the cell membrane and affect AKP, ATPase and SOD. Anthocyanins also may decrease TCA cycle and the biosynthesis of pathogens, leading to the bacterial decomposition and death eventually. The result from this study provides insight on the antimicrobial effect of anthocyanins as potential natural food preservatives.

Technical Abstract: Anthocyanins of wild blueberries were studied for their inhibition of the growth of Listeria monocytogenes, Staphylococcus aureus, Salmonella enteritidis and Vibrio parahaemolyticus. The inhibitory mechanisms of anthocyanins from wild blueberries (Vaccinium uliginosum) were also evaluated. Anthocyanins were obtained using methanol and a C-18 column. The minimum inhibitory/bactericidal concentration (MIC/MBC) of anthocyanins was determined by two-fold serial dilution. Vibrio parahaemolyticus was the most susceptible to anthocyanins with the lowest MIC/MBC for each treatment, followed by S. aureus. After anthocyanins treatment, the membrane permeability and metabolism of four pathogens was assessed by the value of OD260, OD595 and OD630, respectively. The measurement of total protein content and the activity of AKP, ATPase and Superoxide Dismutase were assessed by several protein assay kits. When foodborne pathogens treated with anthocyanins for 2 h, the value of OD260 and OD595 increased, which demonstrated that anthocyanins could destroy the cell membrane. Furthermore, the total protein content and enzymes activity decreased after treatment. With increasing concentration of anthocyanins, the OD630 of L. monocytogenes, S. aureus, S. enteritidis, V. parahaemolyticus decreased by 55%, 71%, 67%, and 79%, respectively. This referred that TCA cycle was decreased, reducing the energy transfer of pathogens and inhibiting their growth and reproduction. The strong antimicrobial effect of Chinese wild blueberry anthocyanins provide application potential in the field of food safety.