Progress 10/01/07 to 09/30/12
Outputs
OUTPUTS: The results of this project has allowed the to identification of effective GRAS antimicrobials that can be utilized as either a direct additive in the product formulation, as an edible biofilm/coating, or as a component of the packaging process to control the growth and survival of biothreat agents in foods. These results will be published in peer-reviewd jouners in the next two months. PARTICIPANTS: Melissa Newman -PI Cetin Karaca, Hayriye -MS student TARGET AUDIENCES: Not relevant to this project. PROJECT MODIFICATIONS: Not relevant to this project.
Impacts
Although protection of food from pathogens and spoilage organisms has been traditionally achieved by chemical methods, in recent years, there is considerable interest to employ natural antimicrobials as an alternative to control the growth of microorganisms due to consumer preference, health and economic concerns. Studies were performed to evaluate the antimicrobial efficacy of natural plant based phenolic compounds (PBPC) as potentials to be used as natural preservatives in food products. Strains of Bacillus, Listeria and Clostridium species were treated with 12 natural PBPCs including; chlorogenic acid, coumarin, curcumin, ellagic acid, (-) epicatechin, eugenol, rosmarinic acid, rutin, tannic acid, thymol, thymoquinone, and xanthohumol. Thymoquinone, xanthohumol and ellagic acid demonstrated the highest antimicrobial efficacy, while all the other PBPCs were also effective being dose and strain dependent. This is the first study concerning the antimicrobial efficacy of PBPCs against Clostridium species. The results demonstrated that the PBPCs have varying antimicrobial activities against both aerobic and anaerobic gram positive foodborne pathogens following 24 hour and 60 hour incubation periods. Natural sources of phenolic compounds contain major antimicrobial components and have great potential to control the growth of pathogens and be used as natural antimicrobials and food preservatives, including long term storage.
Publications
- No publications reported this period
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Progress 01/01/11 to 12/31/11
Outputs
OUTPUTS: Raw and processed foods are vulnerable to contamination during their production, distribution and sale. Thus, a wide variety of chemical preservatives are used in the food industry to prevent the growth of food spoiling and pathogenic bacteria. However, health and economic concerns have led to an intensive search for natural alternatives, such as plant extracts that can safely be used as substitutes for antimicrobials and preservatives to partially or completely inhibit the growth of bacteria. Phenolic compounds, natural plant extracts, are secondary metabolites which have antimicrobial and antioxidant characteristics. studies focused revealing the antimicrobial effects of phenolic compounds, such as Quercetin, Myricetin, Xanthohumol, Coumarin, Curcumin, Rutin, Thymoquinine and Chlorogenic Acid. The main objective was to determine the lowest concentration of phenolics to inhibit the visible growth of the pathogenic bacteria which is recorded as the minimum inhibitory concentration (MIC). These results have been presented in part in abstracts presented at the IFT International meeting PARTICIPANTS: Hayriye Cetin Karaca - graduate student Katherine Akers - research associate Melissa Newman - PI TARGET AUDIENCES: Nothing significant to report during this reporting period. PROJECT MODIFICATIONS: Not relevant to this project.
Impacts
Three of the most common pathogen and food spoilage bacteria E. coli 0157:H7 (ATTC 35150), E. coli 0157:H7( ATTC 43895), and E. coli (swine fecal isolate) were treated with the eight phenolics by using the treatment doses of 100microliter of 5 ppm, 10 ppm, 15 ppm, and 20 ppm of solutions (pH 5-6). Obtained results were compared with the antimicrobial effects of the pure compound, solvent, along with a negative control treatment (no antimicrobial agent and no solvent added). Incubation was performed in Mueller Hinton Broth at 37C for up to 60 hours. The MICs were determined using the broth micro-dilution method and density (OD) assay with Biotek Synergy 4 Multi-Mode Microplate Reader. Our results showed that, all of the selected phenolics inhibited the microbial growth while Xanthohumol, Myricetin and Quercetin showed the highest antimicrobial effect with the MICs of >5 ppm. Natural sources of phenolic compounds contain major antibacterial components and have great potential to be used as natural antimicrobials and food preservatives.
Publications
- No publications reported this period
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Progress 01/01/10 to 12/31/10
Outputs
OUTPUTS: Milk has been identified as a high risk food due to numerous reasons including bulk collection and holding, transportation systems, target consumer populations. Heat treatments applied to each food product shall vary with product and range up to heat treatments used in the commercial food processing industry. Processed cheese currently is processed at temperatures ranging from pasteurization to practical commercial sterilization. Milk processing varies in actual pasteurization treatments (generally exceeds regulatory requirements) to ESL and UHT. Compounds identified as effective in the previous studies, have been coupled with heat treatment to antimicrobial activity using a combination of four holding times at four temperatures. Heat treatments were monitored with a temperature profiling system to compare relative lethality's of each treatment. Effectiveness was determined by enumerating survivors on appropriate recovery media. Milk and processed cheese products held at refrigeration temperature for times approaching normal commercial shelf life of the products. Vegetative pathogens were evaluated similarly in milk and ground beef using stationary phase cells and appropriately lower sub-lethal heat treatments. Heat treatments utilized are intended to have no effect on the normal organoleptic properties of the food product. PARTICIPANTS: Nothing significant to report during this reporting period. TARGET AUDIENCES: Not relevant to this project. PROJECT MODIFICATIONS: Not relevant to this project.
Impacts
Antimicrobial effect of the spices and herbs in combination were achieved throughout the study and was related to the synergistic effects of the spices and herbs in foods.
Publications
- Derrick L. Hammons, A S. Kaan Kurtural, M. C. Newman, and D. A. Potter. 2009. Invasive Japanese beetles facilitate aggregation and injury by a native scarab pest of ripening fruits. Proc Natl Acad Sci. 106(10)3686-3691.
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Progress 01/01/09 to 12/31/09
Outputs
OUTPUTS: Commonly consumed spices and herbs have been used for centuries to incorporate flavor and extend the storage of foods. As natural food additives, spices and herbs are on the verge of a new era and of particular interest because of their known antimicrobial power. This study focuses on the antimicrobial effects of pungent spices and herbs when used in combination with the antimicrobial agent allicin, from garlic. Our objective was to determine antimicrobial effects of cinnamon, cloves, cardamom, tulsi and chilli when used in combination with the antimicrobial agent, allicin. These spices and herbs were used in treatment combinations with allicin for the purpose of decreases the pungent odor and flavors when applied to a food system. Salmonella typhimurium, Escherichia coli, Bacillus cereus, Bacillus subtilis and Bacillus polymyxa, commonly found food spoilage organisms, were treated using the five aforementioned spices and herbs in equal combination with the antimicrobial agent allicin at treatment doses of 0.1uL of 100%, 50%, 25% and 12.5% solutions. Each treatment was compared with the antimicrobial effects of the pure spice or herb, allicin, 95% ethanol, along with a negative control treatment (no antimicrobial agent and no 95% ethanol added). All treatments were stored at 32C for 60 hours and evaluated in triplicate to insure reproducibility. Microbial growth was measured with a Bausch & Lomb Spectronic 70 Spectrophotometer. PARTICIPANTS: Melissa Newman PI Kabby Akers Research Assistant Jennifer Willig Graduate student TARGET AUDIENCES: Nothing significant to report during this reporting period. PROJECT MODIFICATIONS: Current methodology has focused on determine the minimum inhibitory concentration (MIC) of an antibacterial compounds alone and in combination as the maximum dilution of the product that will still inhibit the growth of a test microorganism. The minimum lethal concentration (MLC) of an antibacterial is defined as the maximum dilution of the product that will kill a test organism. Future studies will focus on determining the bacteriostatic characteristics of these compounds when included in food formulations
Impacts
Antimicrobial effect of the spices and herbs in combination with allicin was achieved throughout the study and was related to the synergistic effects of the spices and herbs in combination with allicin. These findings suggest that the pungent odors and off flavors of cinnamon, cloves, cardamom, tulsi and chilli when applied to a food system for the purpose of imparting an antimicrobial effect will be decreased by two fold.
Publications
- No publications reported this period
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Progress 01/01/08 to 12/31/08
Outputs
OUTPUTS: Phenotypic and genotypic antibiotic resistance characteristics of the fecal Lactobacilli and the distribution of tetracycline resistance genes were evaluated for samples collected from farms with different histories of antibiotic use, fecal samples were collected from sows maintained in either an antibiotic-free or a conventional antibiotic-exposed environment. The majority of both farms' fecal lactobacilli isolates were resistant to tetracycline. The percentage of antibiotic-free farm isolates resistant to penicillin and ampicillin was significantly higher than the percentage of resistant isolates from the conventional herd. The percentage of the conventional farm isolates resistant to erythromycin, lincomycin, and clindamycin was significantly higher than the percentages of resistant isolates from the antibiotic-free herd. The majority of isolates from the antibiotic-free herd were also resistant to lincomycin. The majority of isolates from the antibiotic-exposed herd were resistant to four antibiotics while the majority of isolates from the antibiotic-free herd were resistant to two or less antibiotics. Tetracycline resistance genes were detected in fecal, soil, and waste samples from both farms with variable frequencies. All of the ribosomal protection tetracycline resistance genes evaluated were detected in isolates from the antibiotic-free herd while only three were detected in isolates from the antibiotic-exposed herd. Fecal Lactobacilli contribute to the reservoir of resistance in the swine gastrointestinal tract irrespective of antibiotic exposure history. The persistence of phenotypic resistance to multiple antibiotics and tetracycline resistance genes in fecal isolates without selective pressure would indicate the stability of these traits. Specific mechanisms associated with maintenance within this environment are unknown. PARTICIPANTS: Melissa Newman PI, Erica Pettey investigator TARGET AUDIENCES: Nothing significant to report during this reporting period. PROJECT MODIFICATIONS: Not relevant to this project.
Impacts
Phenotypic and genotypic antibiotic resistance characteristics of fecal Lactobacilli and the distribution of tetracycline resistance (TET-R) genes were evaluated for samples collected from an antibiotic-free and a conventional (antibiotic-exposed) swine herd. The majority (97%) of both farms' fecal lactobacilli isolates were resistant to tetracycline. The percentage of antibiotic-free farm isolates resistant to penicillin (32.4%) and ampicillin (31.4%) was significantly (p<0.01) higher than the percentage of resistant isolates from the conventional swine herd. The percentage of the conventional farm isolates resistant to erythromycin (99.3%), lincomycin (100%), and clindamycin (97.8%) was significantly (p<0.01) higher than the percentages of resistant isolates from the antibiotic-free swine herd. Approximately 87% of the isolates from the antibiotic-free swine herd were resistant to lincomycin. The majority (84.7%) of isolates from the conventional swine herd were resistant to four antibiotics. The majority (67.6%) of isolates from the antibiotic-free swine herd were resistant to two or less antibiotics. The mean number of antibiotics in the multi-resistance patterns for isolates from the conventional swine herd (4.11) was significantly (p<0.01) greater than the average (2.49) for the antibiotic-free swine herd. Swine fecal lactobacilli demonstrated tetracycline minimum inhibitory concentrations ranging from 12.5 to 400 μg/ml. The TET-R efflux genes (tetB, tetC, tetG, tetH, tetY, and tetZ) were detected in fecal, soil, and waste samples from both farms with variable frequencies. The TET-R ribosomal protection genes (tetM, tetO, tetQ, tetS, and tetW) were detected in fecal, soil, and waste samples from both farms with variable frequencies. All of the ribosomal protection genes were detected in isolates from the antibiotic-free swine herd while only tet(M), tet(O), and tet(W) were detected in isolates from the conventional swine herd.
Publications
- No publications reported this period
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