Usage
  • 59 views
  • 87 downloads

Effect of starter culture on accumulation of taste active amino acids, free fatty acids, and on survival of pathogenic Escherichia coli in dry fermented beef sausages

  • Author / Creator
    Tang, Kaixing
  • The accumulation of taste active compounds during ripening determines the taste of fermented meats; however, the contribution of defined starter cultures to glutamate during sausage ripening remains unknown. This study investigated the role of lactic acid bacteria and Staphylococcus carnosus on the accumulation of free amino acids during dry sausage fermentation. A sausage model system was developed to ensure control of sausage microbiota throughout ripening. Sausages were produced at the laboratory-scale with defined starter cultures; aseptic controls were fermented without culture addition. Lactobacillus sakei FUA3009, Lactobacillus plantarum, Pediococcus pentosaceus FUA3071, Pediococcus acidilactici were used as single cultures; Staphylococcus carnosus with L. sakei FUA3549 or P. pentosaceus FUA3550 were used as cocktails. The cell counts in aseptic control sausages remained <1 log CFU g-1 throughout 20 d of ripening. The water activity and pH of model sausages were comparable to commercial products. The use of the model system demonstrated that bacterial enzymes influenced the release of free amino acids, even during the initial fermentation stage. Ripening time and starter cultures are important factors determining the accumulation of free amino acids. By controlling the sausage microbiota with clean meat and amino acid decarboxylase negative strains, biogenic amines remained below the detection limit in all products. The increase of total free fatty acids at the end of ripening stage was primarily catalyzed by the endogenous lipase, and the unsaturated fatty acids were further utilized by starter cultures. The sausage model system was also used for a challenge trial with a cocktail of pathogenic E. coli strains; cell counts of pathogenic E. coli were reduced by less than 1 Log CFU g-1 during ripening. The sausage model for control of ripening microbiota will facilitate further studies on the impact of defined cultures on the safety and quality of fermented meats.

  • Subjects / Keywords
  • Graduation date
    Spring 2018
  • Type of Item
    Thesis
  • Degree
    Master of Science
  • DOI
    https://doi.org/10.7939/R3Z892W5M
  • License
    Permission is hereby granted to the University of Alberta Libraries to reproduce single copies of this thesis and to lend or sell such copies for private, scholarly or scientific research purposes only. Where the thesis is converted to, or otherwise made available in digital form, the University of Alberta will advise potential users of the thesis of these terms. The author reserves all other publication and other rights in association with the copyright in the thesis and, except as herein before provided, neither the thesis nor any substantial portion thereof may be printed or otherwise reproduced in any material form whatsoever without the author's prior written permission.