2.04 Theophane Venard School of Biotechnology
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ItemAntibacterial activity of Chrysanthemum indicum, Centella asiatica and Andrographis paniculata on Bacillus cereus and Listeria monocytogenes under Low pH StressClassic food preservation methods do not guarantee to inhibit Bacillus cereus and Listeria monocytogenes growth. The application of natural antibacterial agent is an alternative way to control their growth. Asia herbs, Chrysanthemum indicum, Centella asiatica, and Andrographis paniculata were used in this experiment to test their antibacterial activity under low pH stress. Their antibacterial activities of 95% ethanolic crude extracts were tested on B. cereus and L. monocytogenes 10403S under different low pH stress by agar disc diffusion method. The best antibacterial effect on both bacteria was found at low pH stress condition. Lowering pH also acts as one inhibitory effect. The result of in vitro antibacterial effect as inhibition zone at pH 7.0, 6.5, 6.0, 5.5, showed that the inhibition zone diameters of C. indicum extracts were 7.62±1.18. 7.87±2.35, 6.25±3.06 and 9.50±2.14 cm, while the inhibition zone diameters of C. asiatica extracts were 8.75±1.03, 8.75±2.66, 7.75±2.37 and 9.12±1.96 cm and A. paniculata extracts were 9.75±1.75, 5.87±3.52, 8.5±1.23 and 9.33±1.63 against L. monocytogenes 10403S, respectively. Under the same condition, the inhibition zone diameters of C. indicum extracts at 2.12±0.64, 1.37±0.92, 0.93±0.78 and 6.00±3.25 cm, the inhibition zone diameters of C. asiatica extracts at 0.62±0.44, 2.25±0.46, 1.75±0.28 and 6.50±1.60 cm and A. paniculata extracts at 0.87±0.79, 1.25±0.60, 2.00±1.65 and 6.00±1.31, respectively against B. cereus. All 95% ethanolic crude extracts showed more inhibition effect on L. monocytogenes 10403S than B.cereus. However, the promising active antibacterial compounds in all three herbs are needed to be identified. The MBCs of A. paniculata, C. asiatica and C. indicum showed 4, 16 and >32 µl/ml against B. cereus while A. paniculata and C. asiatica showed 16 and >32 µl/ml against L. monocytogenes 10403S.
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ItemAntibacterial Activity of Thai Red Curry Paste in Kang-Kati (Thai Red Curry) Model on Salmonella enterica Typhimurium DT104b( 2013-06) Patchanee YasurinNowadays food safety becomes an international concern. Natural antibacterial is now become very interesting food safety trend. The investigation on the food itself having antibacterial activity becomes more dynamic. Salmonella sp. has been reported its outbreaks recently in different variety of food. Kang-Kati (Thai red curry) is a Thai cultural dish and also worldwide well-known menu. The Thai red curry paste, Thai red curry’s main ingredients, compose of many herbs including Capsicum annuum (Red chili), Cymbopogon citrates (Lemongrass), Alpinia galangal (Galangal), Allium ascalonicum L (Shallot), Allium sativum (Garlic), Citrus hystrix (kaffir lime), Cuminum cyminum (Cumin). Therefore, this study aimed to investigate the potential of Thai red curry paste in Kang-Kati using fresh coconut milk model as natural antibacterial agent against S. enterica Typhimurium DT104b. Kang-Kati was prepared according to Thai homemade authentic cooking method as it has been served in Thai cuisine and was inoculated with 1% culture. Thai curry paste in-vitro antibacterial activity was evaluated by cell count serial dilution method on SS media every hour for 6 hrs at room temperature. The result showed that the level of S. enterica Typhimurium DT104b in Kang-Kati was significant lower than of positive control (NB) (P<0.05) in 6th hour; 8.32±0.04, 8.02±0.08 log CFU/ml, respectively. The t-test has been done by using SPSS on log CFU/ml with P < 0.05. It is indicated that Thai red curry paste in Kang-Kati model showed promising combinated antibacterial activity against food-borne pathogenic bacteria, S. enterica Typhimurium DT104b.
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ItemThe antimicrobial and shelf-life study of vegetable sanitizer from herbal extracts and Acacia concinna(Willd.) D.C’s pod water( 2015-11) Patchanee YasurinIn the past 3 years, the Centers for Disease Control and Prevention (CDC) reported that there were at least 7 outbreaks in fresh produces, for example; Escherichia coli O121 in raw clover sprouts (2014), E. coli O157:H7 in ready-to-eat salads (2013), and Salmonella Saintpaul in cucumbers (2013). The cleaning of fresh produces is the first step in order to prevent foodborne outbreak. Therefore, this experiment aims to study and develop the shelf life of vegetable sanitizer from Thai herb crude extracts including Cymbopogon citratus (Lemongrass), Citrus hystrix (Kaffir lime), Chrysanthemum indicum (Chrysanthemum) and Acacia concinna (Willd.) D.C’s pod (Som-poi) water compared with 2 commercial brands namely Jirada and Veggie. To achieve this goal, antibacterial activity and shelf-life study were determined by antimicrobial efficiency experiment using total plate count. In this study, the vegetable sanitizer was prepared by adding 1.5% of each 0.2 g/ml crude extracts into Som-poi’s pod water and then sterilized at 121 ºC for 15 minutes. Lactuca sativa (Lettuce) using as vegetable model was soaked in 1 % of the vegetable sanitizer in water for 20 minutes before determination antibacterial activity of the vegetable sanitizer every 2 weeks for 10 weeks. Surprisingly, the results showed that the highest percentage of antimicrobial efficiency was 99.70±0.13. Although the percentage of antimicrobial efficiency decreased significantly after the 6th week; however, antimicrobial efficiency of the vegetable sanitizer remained higher than 90% up to 10 weeks. There was no significant difference of antimicrobial efficiency among 2 commercial brands and the vegetable sanitizer for 8 weeks. In conclusion, the results illustrated hat the vegetable sanitizer from Thai herbal extracts and A. concinna (Willd.) D.C’s pod water was excellent in antibacterial activity as well as a commercial brand however it could be more value in terms of a green vegetable sanitizer.