Antibacterial properties of green tea polyphenols and EGCg

Green tea is often served at sushi restaurants not just for healthy drink, but also known to reduce risk of food poisoning.

Some of the most deadly food poisoning bacteria are very sensitive to green tea polyphenols (catechins).  C. botulinum is commonly found in soil, yet most notable botulism cases come from improperly canned foods.  In order to destroy C. botulinum spores, you must cook at 120C for more than 4 minutes.  In green tea drinks due to its antimicrobial property 85C for 30 minutes can almost completely destroy.  In intestinal tract it is reported that less than 100ppm of green tea catechins is required to achieve MIC for C. botulinum.

Hara et. al. (*1) shows that effects of green tea catechins (green tea polyphenols) on human intestinal bacteria.  Lactobacillus acidophilus and Bifidobacterium bifidum generally considered as beneficial bacteria showed significantly greater minimum inhibitory concentration (MIC) to catechins while Clostridium and Staphylococcus that can cause food poisoning are lower MIC.

Minimum inhibitory concentration of green tea catechins in intestinal bacteria.(*1)
Bacterial strainMinimum inhibitory concentration (ppm)
Staphylococcus aureus IAM 1011450
Vibrio fluvialis JCM 3752200
V. parahaemolyticus IFO 12711200
V. metschnikovii IAM 1039500
Clostridium perfringens JCM 3816400
Clostridium botulinum A. B mixless than 100
Bacillus cereus JCM 2152600
Plesiomonas shigelloides IID No.3100
Aeromonas sobria JCM 2139400
-----------------------------------
Lactobacillus sp. JCM1102greater than 1000
Lactobacillus sp. JCM1059greater than 1000
Lactobacillus sp. JCM1183greater than 1000
Bifidobacterium bifidum JCM 1255greater than 1000
Bifidobacterium bifidum JCM 1275greater than 1000


Minimum inhibitory concentration of green tea catechins against food poisoning bacterial (*1)
Bacterial strainMinimum inhibitory concentration (ppm)
ECECgEGCEGCg
Staphylococcus aureus IAM 1011greater than 800800150250
Vibrio fluvialis JCM 3752800300300200
V. parahaemolyticus IFO 12711800500300200
V. metschnikovii IAM 1039greater than 1000greater than 1000500greater than 1000
Clostridium perfringens JCM 3816greater than 10004001000300
Bacillus cereus JCM 2152greater than 1000600greater than 1000600
Plesiomonas shigelloides IID No.3700100200100
Aeromonas sobria JCM 2139greater than 1000700400300
Clostridium botulinum A. B mixgreater than 1000less than 100300less than 100


*1 Hara et. al. 1989, Journal of the Japanese Society for Food Science and Technology, 36. 951

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