고려대학교

목차

ABSTRACT ...........................................................................................................................i
국문 초록.............................................................................................................................iii
ACKNOWLEDGMENT .....................................................................................................vii
PREFACE...........................................................................................................................viii
TABLE OF CONTENTS .....................................................................................................ix
LIST OF TABLES .............................................................................................................xiii
LIST OF FIGURES.............................................................................................................xv
NOMENCLATURE...........................................................................................................xix
CHAPTER 1: INTRODUCTION..........................................................................................1
CHAPTER 2: LITERATURE REVIEW...............................................................................4
1. Korean mushrooms linked to multinational Listeria spp. outbreak.........................4
2. Bacterial prevalence in Korean enoki mushrooms ..................................................4
3. L. monocytogenes’ contamination pathways in Korean facilities............................5
4. Extending survival and growth of L. monocytogenes during enoki mushroom
cultivation ....................................................................................................................5
5. Acetoin as a Listeria spp. contamination biomarker ...............................................6
6. VOC production profiles by L. monocytogenes.......................................................6
7. Characterization of Enoki mushroom’s volatile terpenes by GC-MS/MS ..............7
8. A pathway to explain higher alcohol production.....................................................8
9. 3-Octanone as a defense mechanism? .....................................................................8
10. Oxygen and carbon dioxide concentrations affect the growth of common food
spoilage microorganisms.............................................................................................9
11. Listeria spp. and Salmonella’s responses under different temperatures..............10
12. Influence of different packaging types on enoki mushroom’s postharvest quality
...................................................................................................................................10
13. Edible coating to reduce L. monocytogenes contamination.................................11
14. Target volatile organic compounds analyzed in this study..................................12
CHAPTER 3: MATERIAL AND METHODS ...................................................................13
1. Experimental Design .............................................................................................13
1.1. Comparative Survey Experiment................................................................13
1.2. Transport and Packaging Simulation Experiment ......................................13
1.3. Substrate Experiment (Fruiting Body vs. Substrate Body).........................13
1.4. Listeria Agar Plates VOCs Experiment......................................................14
1.5. Mushrooms Used for Experiments.............................................................15
2. Sample Preparation................................................................................................16
2.1. Comparative Survey Experiment................................................................16
2.2. Transport and Packaging Simulation Experiment ......................................16
2.3. Substrate Experiment (Fruiting Body VS Substrate Body)........................16
2.4. Listeria Agar Plates VOCs Experiment......................................................17
3. Weight Change ......................................................................................................18
4. Analysis of VOCs..................................................................................................19
4.1. Method for sampling processes in thermal desorption ...............................19
4.1.1. Method for sampling processes in thermal desorption for the Listeria agar
plate VOCs Experiment.....................................................................................19
4.2. Non-invasive analysis through thermal desorption gas chromatographymass
spectrometry .............................................................................................19
5. Bacterial Quantification on Agar Plates ................................................................21
5.1. Agar Plates Preparation ..............................................................................21
5.2. Agar Inoculation.........................................................................................21
5.3. Agar Plate Quantification ...........................................................................22
5.4. Microbiome Taxonomic Profiling ..............................................................22
6. Statistical Analysis.................................................................................................23
CHAPTER 4: RESULTS ....................................................................................................24
1. Comparative survey of Enoki Mushrooms (Flammulina velutipes) in Korea .......24
1.1. Bacterial activity.........................................................................................24
1.2. Headspace gas concentration......................................................................24
1.3. Non-destructive assessment of VOCs of enoki mushrooms and correlations
...........................................................................................................................29
1.4. Microbiome Taxonomic Profiling..............................................................30
2. Transport and temperature simulation of Korean Enoki mushrooms....................35
2.1. Bacterial activity.........................................................................................35
2.2. Headspace gas concentration......................................................................38
2.3. Non-destructive assessment of VOCs of enoki mushrooms under different
treatments ..........................................................................................................41
3. Substrate Experiment (Fruiting Body vs. Substrate Body)....................................46
3.1. Bacterial activity.........................................................................................46
3.2. Non-destructive assessment of VOCs of enoki mushrooms based on
structures............................................................................................................48
4. Listeria Agar Plates VOCs Experiment.................................................................52
4.1. Assessment of VOCs by Suspected Listeria spp. on PALCAM Agar over
time....................................................................................................................52
CHAPTER 5: DISCUSSION ..............................................................................................57
1. Comparative survey of Enoki mushrooms in South Korea ...................................57
1.1. Bacterial Activity........................................................................................57
1.2. Correlations between Headspace Gas Concentration, Bacterial Activity and
Volatile Profiles.................................................................................................58
2. Transport and Packaging Simulation Experiment .................................................59
2.1. Bacterial Activity........................................................................................59
2.2. Headspace Gas Concentration ....................................................................60
2.3. Non-destructive VOC Assessment .............................................................61
3. Substrate Experiment (Fruiting Body vs. Substrate Body)....................................63
3.1. Bacterial activity.........................................................................................63
3.2. Non-destructive VOC Assessment of Structures........................................64
4. Listeria Agar Plates VOCs Experiment.................................................................66
4.1. Assessment of VOCs by Suspected Listeria spp. on PALCAM Agar over
time....................................................................................................................66
5. Limitations and Future Perspectives......................................................................69
CHAPTER 6 : CONCLUSION...........................................................................................70
REFERENCE ......................................................................................................................72
SUPPLEMENTARY MATERIALS ...................................................................................78
A. Experiment 1.2. Weight Loss................................................................................78
B. Experiment 1.2. Environmental Data....................................................................79