College of Agriculture & Natural Resources

Permanent URI for this communityhttp://hdl.handle.net/1903/1598

The collections in this community comprise faculty research works, as well as graduate theses and dissertations.

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Subject: search.filters.subject.antimicrobial

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    Effects of On-Farm Dairy Manure Composting on Tetracycline Content and Nutrient Composition
    (MDPI, 2021-04-15) Schueler, Jenna; Naas, Kayla; Hurst, Jerod; Aga, Diana; Lansing, Stephanie
    This study quantified the potential of farm-scale composting to degrade antibiotics in dairy manure. The compost windrow, consisting of sick cow bedding from a 1000-cow US dairy farm, was managed using the dairy farm’s typical practices and monitored for tetracycline and nutrient composition. Samples were collected over 33 days, which was the time from compost pile formation to land application as fertilizer, and analyzed for solids, antibiotics, and nutrient content. Average tetracycline concentrations at the beginning of the study (452 ng/g DW) were lower than at the end of composting (689 ng/g DW), illustrating that antibiotic degradation was not greater than degradation of the compost solids. Total Kjeldahl nitrogen (TKN) increased from 15.3 to 18.4 g/kg during the composting period due to decreases in solids and likely inhibition of N-mineralization due to the presence of antibiotics. The results indicated that antibiotics were not completely degraded when using the farm’s compost pile management techniques, with antibiotics possibly impacting nitrogen transformation in the compost, which should be considered in nutrient management when using sick cow bedding. Additionally, the results showed that antibiotic degradation during farm-scale composting can vary from reported laboratory-scale due to differences in management, composting duration, and temporal conditions, illustrating the need for more extensive on-farm research including common farm practices and real-world conditions.
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    Inhibitory Effect of Selected Spice and Fruit Seed Extracts on Lipid Oxidation in Fish Oil and Their Radical Scavenging and Antimicrobial Properties
    (2006-09-27) Luther, Marla West; Yu, Liangli; Food Science; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)
    Ethanol extracts of cumun-3 parsley, black currant, green river parsley, Chardonnay grape, Pinot noir grape and black raspberry seed flours and cranberry seed meal were evaluated for their capacity to suppress lipid oxidation, preserve fatty acids, inhibit microbial growth, and scavenge DPPH and peroxyl radicals (ORAC), and total phenolic content (TPC). All tested extracts suppressed lipid oxidation in fish oil. At a concentration range of 2.6-5.3 mg flour or meal equivalents/mL all extracts exhibited antibacterial activity against Escherichia coli and Listeria monocytogenes, except cumun-3 and green river parsley against L. monocytogenes. All tested seed flour and meal extracts exhibited DPPH radical quenching activity. Chardonnay exhibited the strongest ORAC of 663 µmol TE/g and highest TPC of 99 mg GAE/g seed flour. The data from this study suggest the potential of developing natural food preservatives from these seed flours and meal for improving food stability, quality, safety and consumer acceptance.