Application of cranberry concentrate ( Vaccinium macrocarpon) to control Escherichia coli O157:H7 in ground beef and its antimicrobial mechanism related to the downregulated slp, hdeA and cfa

• Published in: Food microbiology Vol. 26; no. 1; pp. 32 - 38
• Main Authors: Wu, Vivian C.H., Qiu, Xujian, de los Reyes, Benildo G., Lin, Chih-Sheng, Pan, Yingjie
• Format: Journal Article
• Language: English
• Published: England Elsevier Ltd 01.02.2009
• Subjects: Animals; Antimicrobial mechanism; Cattle; Colony Count, Microbial; Consumer Product Safety; Cranberry concentrate; Dose-Response Relationship, Drug; Down-Regulation; Escherichia coli; Escherichia coli O157 - drug effects; Escherichia coli O157 - genetics; Escherichia coli O157 - growth & development; Escherichia coli O157:H7; Food Contamination - prevention & control; Food Microbiology; Food Preservation - methods; Food Preservatives - pharmacology; Gene Expression Regulation, Bacterial - drug effects; Gene regulation; Ground beef; Humans; Meat Products - microbiology; Plant Extracts - pharmacology; Polymerase Chain Reaction - methods; Sensory evaluation; Temperature; Time Factors; Vaccinium macrocarpon; Vaccinium macrocarpon - chemistry; Cranberry concentrate; Sensory evaluation; Antimicrobial mechanism; Gene regulation; Escherichia coli O157:H7; Ground beef
• ISSN: 0740-0020; 1095-9998
• DOI: 10.1016/j.fm.2008.07.014

The possible use of cranberry concentrate (CC) as a natural food preservative was studied by examining its antimicrobial effect on the growth of Escherichia coli O157:H7 inoculated in ground beef, its organoleptical effect on beef patties, and its antimicrobial mechanism on the gene regulation level. Inoculated ground beef was added with CC and stored at 4 °C for 5 days. Bacteria were detected on day 0, 1, 3, and 5. Cranberry concentrate (2.5%, 5%, and 7.5% w/w) reduced total aerobic bacteria 1.5 log, 2.1 log, and 2.7 log CFU/g and E. coli O157:H7 0.4 log, 0.7 log, and 2.4 log CFU/g, respectively, when compared to the control on day 5. Fifty panelists evaluated the burgers supplemented with CC. No differences in appearance, flavor, and taste were found among burgers with 0%, 2.5%, and 5% CC. The expression of E. coli O157:H7 cyclopropane fatty acyl phospholipid synthase ( cfa), hypothetical protein ( hdeA), outer membrane porin protein C ( ompC), hyperosmotically inducible periplasmic protein ( osmY), and outer membrane protein induced after carbon starvation ( slp) genes with or without CC (2.5% v/v) treatment was investigated by quantitative real-time PCR. Compared to the control, slp, hdeA, and cfa were markedly downregulated, ompC was slightly downregulated, while osmY was slightly affected.