Title Page
Contents
ABSTRACT 13
Ⅰ. INTRODUCTION 16
Ⅱ. LITERATURE REVIEW 18
1. Retort food 18
1.1. Definition and characteristics of retort food 18
1.2. Market trend of retort food 19
2. Food preservation technology 21
2.1. Retort processing 21
2.2. Superheated steam sterilization 22
3. Spore-forming bacteria responsible for food spoilage 23
3.1. Clostridium botulinum 23
3.2. Geobacillus stearothermophilus 24
Ⅲ. MATERIALS AND METHODS 25
1. Analysis of microbiological contamination in Budaejjigae 25
1.1. Sample preparation 25
1.2. Quantitative analysis 26
1.3. Qualitative analysis 33
2. Confirmation of sterilization effect 34
2.1. Bacterial strains 34
2.2. Preparation of bacterial culture 34
2.3. Preparation of spore suspension 35
2.4. Sample preparation and inoculation 36
2.5. Sterilization processing of Budaejjigae 37
3. Evaluation of thermal processing equivalence 37
3.1. D-value 37
3.2. F-value 39
4. Statistical analysis 40
Ⅳ. RESULTS AND DISCUSSION 41
1. Evaluation of microbiological contamination in Budaejjigae 41
2. Evaluation of retort processing effect 42
2.1. Spore inactivation 42
2.2. D-value 50
2.3. F-value 53
3. Evaluation of SHS sterilization effect 54
3.1. Spore inactivation 54
3.2. D-value 62
3.3. F-value 66
Ⅴ. SUMMARY AND CONCLUSION 71
Ⅵ. REFERENCE 74
ABSTRACT IN KOREAN 85
Table 1. Food type of ready-to-eat and convenience foods 20
Table 2. colA gene primers designed for the detection of Clostridium sporogenes 29
Table 3. Gv2F/Gv3R-M gene primers designed for the detection of Geobacillus stearothermophilus 31
Table 4. PCR cycles for identification of Clostridium sporogenes and Geobacillus stearothermophilus 32
Table 5. Microbiological qualitative analysis result of Budaejjigae 45
Table 6. Microbiological quantitative analysis result of Budaejjigae 46
Figure 1. PCR assay for identifying Clostridium sporogenes. 43
Figure 2. PCR assay for identifying Geobacillus stearothermophilus. 44
Figure 3. Retort processing effect at 120℃ on spore reduction of Clostridium sporogenes. 48
Figure 4. Retort processing effect at 120℃ on spore reduction of Geobacillus stearothermophilus. 49
Figure 5. Graphical decimal reduction time of Clostridium sporogenes exposed to retort processing at 120℃. 51
Figure 6. Graphical decimal reduction time of Geobacillus stearothermophilus exposed to retort processing at 120℃. 52
Figure 7. Superheated steam sterilization effect at 120℃ on spore reduction of Clostridium sporogenes. 55
Figure 8. Superheated steam sterilization effect at 130℃ on spore reduction of Clostridium sporogenes. 56
Figure 9. Superheated steam sterilization effect at 140℃ on spore reduction of Clostridium sporogenes. 57
Figure 10. Superheated steam sterilization effect at 120℃ on spore reduction of Geobacillus stearothermophilus. 59
Figure 11. Superheated steam sterilization effect at 130℃ on spore reduction of Geobacillus stearothermophilus. 60
Figure 12. Superheated steam sterilization effect at 140℃ on spore reduction of Geobacillus stearothermophilus. 61
Figure 13. Graphical decimal reduction time of Clostridium sporogenes exposed to superheated steam at 120℃. 63
Figure 14. Graphical decimal reduction time of Clostridium sporogenes exposed to superheated steam at 130℃. 64
Figure 15. Graphical decimal reduction time of Clostridium sporogenes exposed to superheated steam at 140℃. 65
Figure 16. Graphical decimal reduction time of Geobacillus stearothermophilus spores exposed to superheated steam at 120℃. 68
Figure 17. Graphical decimal reduction time of Geobacillus stearothermophilus spores exposed to superheated steam at 130℃. 69
Figure 18. Graphical decimal reduction time of Geobacillus stearothermophilus spores exposed to superheated steam at 140℃. 70