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

  • Dry fermented sausages
  • umami
  • free amino acid
  • sterile sausage model
  • shiga-toxin producing E. coli
  • glutamate

• Graduation date

  Spring 2018

• Type of Item

  Thesis

• Degree

  Master of Science

• DOI

  https://doi.org/10.7939/R3Z892W5M

• License

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