title: Development of a quantitative PCR assay for rapid detection of Lactobacillus plantarum and Lactobacillus fermentum in cocoa bean fermentation.
abstract: To monitor dominant species of lactic acid bacteria during cocoa bean fermentation, i.e. Lactobacillus plantarum and Lactobacillus fermentum, a fast and reliable culture-independent qPCR assay was developed. A modified DNA isolation procedure using a commercial kit followed by two species-specific qPCR assays resulted in 100% sensitivity for L. plantarum and L. fermentum. Kruskal-Wallis and post-hoc analyses of data obtained from experiments with cocoa beans that were artificially spiked with decimal concentrations of L. plantarum and L. fermentum strains allowed the calculation of a regression line suitable for the estimation of both species with a detection limit of 3 to 4 Log cells/g cocoa beans. This process was successfully tested for efficacy through the analyses of samples from laboratory-scale cocoa bean fermentations with both the qPCR assay and a culture-dependent method which resulted in comparable results.
authors.affiliation: Institute of Food and Beverage Innovation, Zurich University of Applied Sciences, Wädenswil, Switzerland.
authors.forename: Livia
authors.initials: L
authors.lastname: Schwendimann
authors.affiliation: Institute of Applied Simulation, Zurich University of Applied Sciences, Wädenswil, Switzerland; PrognosiX AG, Wädenswil, Switzerland.
authors.forename: Peter
authors.initials: P
authors.lastname: Kauf
authors.affiliation: Institute of Food and Beverage Innovation, Zurich University of Applied Sciences, Wädenswil, Switzerland.
authors.forename: Lars
authors.initials: L
authors.lastname: Fieseler
authors.affiliation: Institute of Food and Beverage Innovation, Zurich University of Applied Sciences, Wädenswil, Switzerland.
authors.forename: Corinne
authors.initials: C
authors.lastname: Gantenbein-Demarchi
authors.affiliation: Institute of Food and Beverage Innovation, Zurich University of Applied Sciences, Wädenswil, Switzerland. Electronic address: susanne.miescher-schwenninger@zhaw.ch.
authors.forename: Susanne
authors.initials: S
authors.lastname: Miescher Schwenninger
mesh_terms: D002099:Cacao / Q000378:metabolism / Q000382:microbiology*; D005285:Fermentation; D052197:Limosilactobacillus fermentum / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism*; D048191:Lactiplantibacillus plantarum / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism*; D060888:Real-Time Polymerase Chain Reaction / Q000379:methods*
keywords: Cocoa bean fermentation; Lactobacillus fermentum; Lactobacillus plantarum; qPCR