Progress 10/01/12 to 09/30/17
Outputs
Target Audience:Research to determine the ability of various animal derived fats to support the survival of Salmonella during storage. A four strain Salmonella cocktail was inoculated into beef tallow, pig lard, and duck fat. All of the animal fats supported the survival of the bacteria over seven days at 26?C and 37?C storage. The signifciance of these results demonstrate that animal fats may be a source of Salomonella contamination. This is particullarily important observation in association with the large number of Salmonella recalls associated with pet foods Changes/Problems:
Nothing Reported
What opportunities for training and professional development has the project provided?Gradute studendts are participating in the research and writting the papers How have the results been disseminated to communities of interest?Under review What do you plan to do during the next reporting period to accomplish the goals?
Nothing Reported
Impacts
What was accomplished under these goals?
Phenolic compounds are one of the most diverse groups of secondary metabolites found in edible plants. They are found in a wide variety of fruits, vegetables, nuts, seeds, stems and flowers as well as tea, wine, propolis and honey, and represent a common constituent of the human diet. The exploration of natural antimicrobials for food preservation receives increased attention due to consumer awareness of natural food products and a growing concern of microbial resistance towards conventional preservatives. The use of phenolic compounds as antimicrobial agents in animal feeds could potentially provide additional benefits, including dual-function effects of both preservation and delivery health benefits. Knowing the antimicrobial effect of the phenolic compounds from several kinds of edible plants on pathogenic microorganisms, it is possible to search new strategies to combine the synergic antimicrobial effects of phenolic compounds with their natural biological properties. The results may permit the formulation of new products to be used as feed additives. The location and mechanisms of action in the bacterial cell of bioactive plant compounds such as degradation of the cell wall, damage to cytoplasmic membrane and membrane proteins, leakage of contents out of the cell, coagulation of cytoplasm, and depletion of the proton motive force have been reported. The mode of action of essential oils is found to be concentration dependent, indicating that low concentrations inhibit enzymes associated with energy production, while higher amounts may precipitate proteins. In general, variations in antimicrobial activities among bacteria may reflect differences in cell surface structures between Gram-negative and Gram-positive species. Lactobacillus spp. and Staphylococcus aureus (Gram-positive) appeared more susceptible to the action of phenolic acids than Gram-negative bacteria such as Escherichia coli and Pseudomonas aeruginosa. Mutations of the lpxC and tolC genes on E. coli seemed to amplify the phenolic acid antimicrobial mechanisms of action against Gram-negative species. Also, the number and position of substitutions in the benzene ring of the phenolic acids and the saturated side-chain length influence the antimicrobial potential of the phenolic acids against the different microorganisms, but in different ways. Active compounds such as thymol, eugenol, and carvacrol have been shown to cause disruption of the cellular membrane, inhibition of ATPase activity, and release of intracellular ATP and other constituents of several microorganisms such as E. coli, E. coli O157:H7, Listeria monocytogenes, Lactobacillus sakei, Pseudomonas aeruginosa, Salmonella enteritidis, and Staphylococcus aureus. Although the antimicrobial activity of some phenolic compounds has been previously reported, the response after the long term exposure was not reported. Moreover, thymoquinine, xanthohumol and thymol have not been included in antimicrobial studies and antimicrobial activity of chlorogenic acid, curcumin, (-) epicatechin, eugenol, myricetin, quercetin and rutin have not been reported broadly on pathogenic Salmonella and E. coli. Objectives of this research included (1) to evaluate the antimicrobial activity of selected natural phenolic compounds extracted from herbs, spices, vegetables, and fruits against Gram-negative foodborne pathogens: Escherichia coli, Escherichia coli 0157:H7, Salmonella paratyphi, Salmonella cholerasuis subsps. and Salmonella enteridis, (2) to determine the MIC of the natural phenolic compounds and (3) to compare the antimicrobial activities between 24 hours and 60 hours of incubation.
Publications
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Progress 10/01/14 to 09/30/15
Outputs
Target Audience:
Nothing Reported
Changes/Problems:
Nothing Reported
What opportunities for training and professional development has the project provided?Graduate student training and experience How have the results been disseminated to communities of interest?Research publications What do you plan to do during the next reporting period to accomplish the goals?Build upon the current work specifically incorporating gut microflora on meat products
Impacts
What was accomplished under these goals?
We evaluated the antimicrobial effects of natural phenolic compounds (PC) extracted from vegetables, fruits, herbs and spices; to inhibit the visible growth of Gram-negative foordborne bacteria which is defined as the minimum inhibitory concentration (MIC). Strains of Escherichia coli and Salmonella species were treated with natural PCs including; chlorogenic acid, curcumin, (-) epicatechin, eugenol, myricetin, quercetin, rutin, thymol, thymoquinone, and xanthohumol. Concentrations of 5, 10, 15, and 20 ppm of each compound were evaluated by broth micro-dilution method and the MICs were determined by using optical density (OD) after 24 an 60 hours of incubation. Structural alterations in treated bacteria were observed via scanning electron microscopy. For E.coli, thymoquinone showed the highest inhibition, followed by rutin, (-) epicatechin and myricetin (MIC<20 ppm for all), while Salmonella was most sensitive to (-) epicatechin (MIC<15 ppm), followed by thymoquinone, rutin and myricetin (MIC<20 ppm for all) following 60 hours of incubation. The results demonstrated that the PCs have varying antimicrobial activities against foodborne pathogens following 24 and 60 hour incubation periods. Natural sources of PCs contain major antibacterial components and have great potential to be used as natural antimicrobials and do not contribute to development of antibiotic resistance.
Publications
- Type:
Journal Articles
Status:
Published
Year Published:
2015
Citation:
ANTIMICROBIAL EFFICACY OF PLANT PHENOLIC COMPOUNDS AGAINST SALMONELLA AND ESCHERICHIA COLI
Food Bioscience Melissa C. Newman and Dr. Hayriye Cetin-Karaca
- Type:
Conference Papers and Presentations
Status:
Published
Year Published:
2015
Citation:
Inactivation of B. cereus in reconstituted infant rice cereal by trans-cinnamaldehyde Hayriye Cetin-Karaca and Melissa Newman
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Progress 10/01/13 to 09/30/14
Outputs
Target Audience:
Nothing Reported
Changes/Problems:
Nothing Reported
What opportunities for training and professional development has the project provided? Networking with other universities. How have the results been disseminated to communities of interest? Abstracts and a paper is currently in preparation What do you plan to do during the next reporting period to accomplish the goals? Currently plan to add promising antimicrobials to animal diets.
Impacts
What was accomplished under these goals?
The efficacy of various organic and natural compounds in enhancing the safety and extending the shelf- life of fresh and further processed refrigerated and frozen variety meat products destined for export were determined. Pork hearts, livers, kidneys and lungs were harvested, subjected to antimicrobial treatment and either inoculated with antibiotic resistant Salmonella sp cocktail or further processed into a raw chunked and formed products containing antimicrobials and then inoculated, and sampled on Days 1,7,14,21, under refrigerated storage (40 F) or Days 28 and 42 under frozen storage (0 F). Antimicrobial treatments consisted of lactic acid (2%), lactic acid plus sodium bisulfate (2%), coumarin (200 ppm), (-) epicatechin (200 ppm), and coumarin plus (-) epicatechin (200 ppm). All products had natural levels of contamination at harvest at log 103-104 for APC and salmonella. Lactic acid was the most effective in minimizing microbial growth in individual organs over the fresh storage time. As expected, frozen storage was a good deterrent to microbial growth over the 42 day storage period. Further, once variety meats were processed into a processed product the addition of lactic acid was beneficial in minimizing microbial growth in both fresh (day 28) and frozen (day 42) sample periods. Finally, in inoculated products, lactic acid and the lactic acid plus sodium bisulfate combination both decreased salmonella populations over the 28 days of storage indicating their ability to be utilized as a promising antimicrobial for variety meats.
Publications
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Progress 10/01/12 to 09/30/13
Outputs
Target Audience:
Nothing Reported
Changes/Problems:
Nothing Reported
What opportunities for training and professional development has the project provided? This research will allow for the support of gratuate students 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? Continued identification of natural antimoicrobials.
Impacts
What was accomplished under these goals?
In an attempt to identify natural compounds to replace the use of antibiotics.The antimicrobial effects of natural phenolic compounds (PC) extracted from vegetables, fruits, herbs and spices; to inhibit the visible growth of Gram-negative pathogenic bacteria which is defined as the minimum inhibitory concentration (MIC). Strains of E. coli and Salmonella species were treated with natural PCs including; chlorogenic acid, curcumin, (-) epicatechin, eugenol, myricetin, quercetin, rutin, thymol, thymoquinone, and xanthohumol. Concentrations of 5, 10, 15, and 20 ppm of each compound were evaluated by broth micro-dilution method and the MICs were determined by using optical density (OD). For E.coli, thymoquinone showed the highest inhibition, followed by rutin, (-) epicatechin and myricetin (MIC<20 ppm for all), while Salmonella was most sensitive to (-) epicatechin (MIC<15 ppm), followed by thymoquinone, rutin and myricetin (MIC<20 ppm for all) following 60 hours of incubation. The results demonstrated that the PCs have varying antimicrobial activities against foodborne pathogens following 24 and 60 hour incubation periods. Natural sources of PCs contain major antibacterial components and have great potential to be used as natural antimicrobials and food preservatives, during long term storage.
Publications
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