광센서 측정에 의한 유산균 생육 측정 방법에 대한 연구

Abstract

The measurement method of lactic acid bacteria using photodiode was studied. The photodiode measurement was based on the principle that the fluorescent material was detected at a wavelength of 460 nm when irradiated with UV of 340 nm. The growth of lactic acid bacteria on the light source was investigated in MRS and kimchi filtrate, and the experiment was applied to Kimchi. The wavelength used in this study is UV-A, which is harmless but can be damaged by continuous exposure. Therefore, the morphological characteristics of the lactic acid bacteria and the safety characterization of the lactic acid bacteria were examined when exposed to the light source. Six strains of lactic acid bacteria isolated from Kimchi were inoculated into MRS broth and cultivated at 30 ℃ for 72 hours, at 10℃ for 10 days and at -1.5 ℃ for 5 weeks. Since the photodiode can be detected by measuring at a bacterial cell count of 8 log CFU/mL or more, the number of bacteria is maximized at the optimum culture temperature of 30℃ so that the Lactobacillus spp., Leuconostoc spp., Weissella spp. classification. At 10℃ and -1.5℃, the photodiode values of lactic acid bacteria grown well at each temperature were changed. At -1.5 ℃, W. koreensis SK showed more than 8 log CFU/mL and the photodiode values of 6 kinds of lactic acid bacteria were similar even though the number of W. koreensis SK increased to the maximum. In kimchi filtrate, at 30℃, the number of bacteria increased to 8~9 log CFU/mL as the growth of microorganism was similar to that of MRS. At 15 ℃, the growth of the bacteria slowly developed and showed a growth rate of 8 log CFU/mL. Although the change of the photodiode value was smaller than 30 ℃, classification was possible according to the photodiode value in each species. At 4℃, fermentation mode (6.5℃,117hours → -2.0℃) and storage mode (-1.5℃), the maximum growth of 5 lactic acid bacteria except W. koreensis SK was 5~7 log CFU/mL. Therefore, the difference of the photodiode value according to the bacteria was insignificant. In D kimchi, the fermentation mode of fermented kimchi was significantly increased at 1 week after storage and then increased again at 12 weeks after fermentation. In the storage mode, there was no significant increase in the photodiode value until 8 weeks of storage, but it increased significantly at 12 weeks of storage. In S and U kimchi, in the fermentation mode all showed significant increase at 2 weeks of storage and increased again at 8 weeks of storage. In the storage mode, the change of the photodiode value was small until 4 weeks of storage, but the photodiode value increased significantly at 8 weeks of storage. There was no change in safety test presence or absence of the light source that the hemolytic test, enzyme activity test, and antibiotic resistance test. However, at -1.5 ℃, Lactobacillus plantarum HD1 was found to be activated after more initial incubation time after light exposure.