Progress 04/01/13 to 09/30/16
Outputs
Target Audience:Farmers, food manufacturers, and consumers. Changes/Problems:
Nothing Reported
What opportunities for training and professional development has the project provided?
Nothing Reported
How have the results been disseminated to communities of interest?The results were presented at the Institute of Food Technologists Annual Meetings. What do you plan to do during the next reporting period to accomplish the goals?
Nothing Reported
Impacts
What was accomplished under these goals?
Passion fruit, guava, noni, lime and java plum were obtained from local farms and grocery stores. Juice was squeezed from these fruits and filtered sterilized with 0.45-μm membranes. The agar well diffusion assay was conducted to determine the antimicrobial potential of these juices against Escherichia coli O157:H7, Salmonella Typhimurium, and Listeria monocytogenes. All juices generated inhibition zones against E. coli O157:H7 and S. Typhimurium. In comparison, lime juice and java plum juice possessed stronger antimicrobial properties than the others. Lime juice generated inhibition zones of 2.2 cm and 3.5 cm against S. Typhimurium and L. monocytogenes, respectively. Its minimum inhibitory concentration was determined as 12.5% and 6.25% against S. Typhimurium and L. monocytogenes, respectively. Java plum juice generated inhibition zones of 2.6 cm and 2.4 cm against S. Typhimurium and L. monocytogenes, respectively. Secondly, the antimicrobial activities of diluted lime juice and java plum juice were further confirmed in water and nutrient broth inoculated with the pathogenic bacteria. The survival of the bacteria in water and nutrient broth was determined on non-selective plate count agar (PCA). S. Typhimurium and L. monocytogenes in water supplemented with 50% lime juice were inactivated at room temperature in 3 and 48 h, respectively. S. Typhimurium was inactivated in the 25% and 12.5% treatments in 4 and 8 h, respectively. In nutrient broth, all tested strains grew to 8-9 log CFU/ml in 12 h. S. Typhimurium was most sensitive to the lime juice treatments. The 50%, 25%, and 12.5% treatments killed S. Typhimurium in 10 min, 3 h, and 8 h, respectively. The 50% treatment killed E. coli O157:H7 and L. monocytogenes in 8 and 5 h, respectively. The 25% treatment inactivated E. coli O157:H7 and L. monocytogenes in 24 and 12 h, respectively. All three tested pathogenic bacteria in nutrient broth supplemented with 50% java plum juice were killed within 12 h. Thirdly, S. Typhimurium was used as a representative pathogen to test its susceptibility to lime juice in a liquid food model. Orange juices containing 25% and 12.5% lime juice were inoculated with the bacteria cells to reach 5 log CFU/ml and incubated at 7°C for 96 h. S. Typhimurium in the juices was recovered on PCA at 35°C for 2 h and then overlaid with selective xylose lysine deoxycholate (XLD) agar. Supplementation with 12.5% and 25% lime juice reduced the pathogen in orange juice by 1.7 and 3.0 logs, respectively, in 72 h. Fourthly, the efficacy of java plum juice for controlling pathogenic bacteria on cantaloupe was determined. Fresh cut cantaloupe inoculated with the pathogens were dipped for 1 hour in water and java plum juices of different concentrations before being stored at 7°C for 8 days. S. Typhimurium and L. monocytogenes in the cantaloupe were recovered on nonselective PCA before being overlaid with corresponding selective agar media. Under refrigeration, both L. monocytogenes and S. Typhimurium were able to grow on cut cantaloupe. When the fruit was treated with 50% java plum juice, the growth of L. monocytogenes was restrained. Comparing to the control, the 50% treatment significantly reduced the count of S. Typhimurium by 0.67, 2.86, and 3.41 logs on day 0, day 4, and day 8, respectively. Finally, chemical analysis was conducted on java plum juice to determine its acidity and total phenolic, tannin and anthocyanin contents. The pH of java plum juice was 3.12. The total phenolic, tannin, and anthocyanin contents were measured at 201.4 mg GAE/100 ml, 91.5 mg GAE/100 ml, and 104.2 mg cyd 3-glu/100 ml, respectively. To sum up, the tested tropical fruit juices have strong antimicrobial effect on common foodborne pathogenic bacteria. Their antimicrobial properties may be attributed to their high contents of organic acids and phenolic compounds. These juices may provide an alternative and green solution for enhancing the microbiological safety of food.
Publications
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Progress 10/01/14 to 09/30/15
Outputs
Target Audience:Farmers, food manufacturers, and consumers. Changes/Problems:
Nothing Reported
What opportunities for training and professional development has the project provided?
Nothing Reported
How have the results been disseminated to communities of interest?The results were presented at the 2015 International Association of Food Protection Annual Meeting in Portland, Oregon. What do you plan to do during the next reporting period to accomplish the goals?We plan to determine the efficacy of extracts from selected tropical fruits for controlling the three pathogenic bacteria on fresh-cut lettuce and alfalfa sprouts.
Impacts
What was accomplished under these goals?
The effect of passion fruit and Wuweizi (Schisandra chinensis) extracts on the survival of major foodborne pathogenic bacteria in synthetic and food models was investigated. Passion fruits were washed and cut into pieces. Juice was squeezed from the sliced flesh and filtered with 0.45 µM membranes. Agar well diffusion assay indicated that passion fruit extract cannot inhibit the growth of Escherichia coli O157:H7, Listeria monocytogenes, or Salmonella Typhimurium. Meanwhile, ten grams of dry Wuweizi fruits were boiled in 200 ml of distilled water for 45 min. Various dilutions of the extract were tested against the three pathogenic bacteria via the agar well diffusion assay as well as in nutrient broth. In addition, pasteurized orange juice supplemented with 5% Wuweizi extract was separately inoculated at 6 logCFU/ml with the three pathogens and stored at 7°C or 21°C. Over time the pathogens in the juice were enumerated on plate count agar. Finally, chemical analysis was conducted on the Wuweizi extract to determine its acidity, and total phenolic, flavonoid and anthocyanin contents. Wuweizi extract generated inhibition zones of 1.58, 2.78, and 1.63 cm against E. coli O157:H7, L. monocytogenes, and S. Typhimurium, respectively. L. monocytogenes and S. Typhimurium in nutrient broth containing 2.5% Wuweizi extract were killed within 6 h. At 21°C, the extract at 5% inactivated all three pathogens in orange juice within 24 h. At 7°C, L. monocytogenes in orange juice was killed within 2 d whereas E. coli O157:H7 or S. Typhimurium did not survive longer than 4 d. The pH of Wuweizi extract was 2.51. The total phenolic, flavonoid, and anthocyanin contents were measured at 851 mg GAE/L, 64.3 mg quercetin/L, and 22.9 mg cyd 3-glu/L, respectively. The antimicrobial property of Wuweizi extract may be attributed to its high contents of organic acids and phenolic compounds.
Publications
- Type:
Conference Papers and Presentations
Status:
Published
Year Published:
2015
Citation:
Zhang, G., and Li, Y. 2015. Antimicrobial effect of Wuweizi (Schisandra chinensis) extracts on foodborne pathogenic bacteria in synthetic media and orange juice. Journal of Food Protection 78: S251
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Progress 10/01/13 to 09/30/14
Outputs
Target Audience: Farmers, food manufacturers, and consumers. Changes/Problems:
Nothing Reported
What opportunities for training and professional development has the project provided?
Nothing Reported
How have the results been disseminated to communities of interest? The results were presented at the Institute of Food Technologists Annual Meeting. What do you plan to do during the next reporting period to accomplish the goals? The antimicrobial activity of other tropical fruits will be tested.
Impacts
What was accomplished under these goals?
The antimicrobial activities of java plum juice against S. Typhimurium and L. monocytogenes were first tested using the agar well diffusion assay as well as in nutrient broth. Additionally, fresh cut cantaloupe inoculated with the pathogens were dipped for 1 hour in water (control), 12.5%, 25%, or 50% java plum juices before being stored at 7°C for 8 days. S. Typhimurium and L. monocytogenes in the cantaloupe were recovered on nonselective plate count agar before being overlaid with corresponding selective agar media. Finally, chemical analysis was conducted on java plum juice to determine its acidity and total phenolic, tannin and anthocyanin contents. Java plum juice generated inhibition zones of 2.6±0.5 and 2.4±0.2 cm against S. Typhimurium and L. monocytogenes, respectively. These pathogens in nutrient broth supplemented with 50% java plum juice were killed within 12 h. Under refrigeration, both L. monocytogenes and S. Typhimurium were able to grow on cut cantaloupe. When the fruit was treated with 50% java plum juice, the growth of L. monocytogenes was restrained. Comparing to the control, the 50% treatment significantly reduced the count of S. Typhimurium by 0.67, 2.86, and 3.41 logs on day 0, day 4, and day 8, respectively. The pH of java plum juice was 3.12±0.02. The total phenolic, tannin, and anthocyanin contents were measured at 201.4±69.1 mg GAE/100 ml, 91.5±17.3 mg GAE/100 ml, and 104.2±13.5 mg cyd 3-glu/100 ml, respectively. The antimicrobial property of java plum juice may be attributed to its high contents of organic acids and phenolic compounds. It provides an alternative and green solution to enhance the microbiological safety of cut cantaloupe.
Publications
- Type:
Conference Papers and Presentations
Status:
Published
Year Published:
2014
Citation:
Ishimoto, J. and Li, Y. 2014. Antimicrobial effect of java plum (Syzygium cumini) juice on Salmonella Typhimurium and Listeria monocytogenes in fresh cut cantaloupe. Institute of Food Technologists Annual Meeting, paper no. 175-01. New Orleans, LA
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Progress 04/01/13 to 09/30/13
Outputs
Target Audience: Farmers, food manufacturers, and consumers Changes/Problems:
Nothing Reported
What opportunities for training and professional development has the project provided?
Nothing Reported
How have the results been disseminated to communities of interest?
Nothing Reported
What do you plan to do during the next reporting period to accomplish the goals? We will test the antimicrobial activity of three other tropical fruits. The efficacy of extracts from selected tropical fruits for controlling Salmonella, E. coli O157:H7 and L. monocytogenes on fresh-cut fruits will be determined.
Impacts
What was accomplished under these goals?
Ripe guava, noni, and lime were obtained from local farms and grocery stores. The fruits were washed and sliced into pieces. Juice was squeezed from the sliced fruits and filtered with 0.45-μm membranes. The agar well diffusion assay was conducted to determine the antimicrobial potential of guava, noni and lime juices against Escherichia coli O157:H7, Salmonella Typhimurium, and Listeria monocytogenes. Guava juice generated inhibitions zones of 1.0 and 2.0 cm in diameter against E. coli O157:H7 and S. Typhimurium, respectively. Noni juice generated inhibitions zones of 1.1, 1.2, and 1.7 cm against E. coli O157:H7, S. Typhimurium, and L. monocytogenes, respectively. In comparison, lime juice possessed the strongest antimicrobial properties. It generated inhibition zones of 2.7, 2.2, and 3.5 cm against E. coli O157:H7, S. Typhimurium, and L. monocytogenes, respectively. The minimum inhibitory concentration of lime juice was determined as 25%, 12.5%, and 6.25% against E. coli O157:H7, S. Typhimurium, and L. monocytogenes, respectively. Moreover, the antimicrobial activity of diluted lime juice was further confirmed in water and nutrient broth inoculated with the pathogenic bacteria. The survival of the bacteria in water and nutrient broth was determined on non-selective plate count agar (PCA). S. Typhimurium and L. monocytogenes in water supplemented with 50% lime juice were inactivated at room temperature in 3 and 48 h, respectively. E. coli O157:H7 was not completely inactivated in 48 h. But the 50% treatment showed a 4-log reduction. S. Typhimurium was inactivated in the 25% and 12.5% treatments in 4 and 8 h, respectively. In nutrient broth, all tested strains grew to 8-9 log CFU/ml in 12 h. S. Typhimurium was most sensitive to the lime juice treatments. The 50%, 25%, and 12.5% treatments killed S. Typhimurium in 10 min, 3 h, and 8 h, respectively. The 50% treatment killed E. coli O157:H7 and L. monocytogenes in 8 and 5 h, respectively. The 25% treatment inactivated E. coli O157:H7 and L. monocytogenes in 24 and 12 h, respectively. Finally, S. Typhimurium was used as a representative pathogen to test its susceptibility to lime juice in a liquid food model. Orange juices containing 25% and 12.5% lime juice were inoculated with the bacteria cells to reach 5 log CFU/ml and incubated at 7°C for 96 h. S. Typhimurium in the juices was recovered on PCA at 35°C for 2 h and then overlaid with selective xylose lysine deoxycholate agar. Supplementation with 12.5% and 25% lime juice reduced the pathogen in orange juice by 1.7 and 3.0 logs, respectively, in 72 h. In conclusion, lime juice has strong antimicrobial effect on tested foodborne pathogenic bacteria. It may provide an alternative and green solution to enhance the microbiological safety of food.
Publications
- Type:
Conference Papers and Presentations
Status:
Published
Year Published:
2013
Citation:
Li, Y., Ishimoto, J., Dong, J., Liang, N., Castro, A., and Iwaoka, W. 2013. Antimicrobial effect of Lime juice on Salmonella Typhimurium in shrimp. Institute of Food Technologists Annual Meeting, paper no. 198-07. Chicago, IL
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