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ABSTRACT: These studies evaluated the bacterial level of unwashed and washed shell eggs from caged and cage-free laying hens. Hy-Line W-36 White and Hy-Line Brown laying hens were housed on all wire slats or all shavings floor systems. On the sampling days for experiments 1, 2, and 3, 20 eggs were collected from each pen for bacterial analyses. Ten of the eggs collected from each pen were washed for 1 min with a commercial egg-washing solution, whereas the remaining 10 eggs were unwashed before sampling the eggshell and shell membranes for aerobic bacteria and coliforms (experiment 1 only). In experiment 1, the aerobic plate counts (APC) of unwashed eggs produced in the shavings, slats, and caged-housing systems were 4.0, 3.6, and 3.1 log(10) cfu/mL of rinsate, respectively. Washing eggs significantly (P < 0.05) reduced APC by 1.6 log(10) cfu/mL and reduced the prevalence of coliforms by 12%. In experiment 2, unwashed eggs produced by hens in triple-deck cages from 57 to 62 wk (previously housed on shavings, slats, and cages) did not differ, with APC ranging from 0.6 to 0.8 log(10) cfu/mL. Washing eggs continued to significantly reduce APC to below 0.2 log(10) cfu/mL. In experiment 3, the APC for unwashed eggs were within 0.4 log below the APC attained for unwashed eggs in experiment 1, although hen density was 28% of that used in experiment 1. Washing eggs further lowered the APC to 0.4 to 0.7 log(10) cfu/mL, a 2.7-log reduction. These results indicate that shell bacterial levels are similar after washing for eggs from hens housed in these caged and cage-free environments. However, housing hens in cages with manure removal belts resulted in lower APC for both unwashed and washed eggs (compared with eggs from hens housed in a room with shavings, slats, and cages).
Poultry Science 07/2011; 90(7):1586-93. · 1.73 Impact Factor
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ABSTRACT: This study compared surface and deep eggshell aerobic bacteria recovered by the rinse and crush-and-rub sampling methods for commercial hatching eggs after treatment with sanitizers. Eggs were arranged into 5 treatments consisting of no treatment, water, and 3 sanitizers. The sanitizers were H(2)O(2), phenol, and Q(4)B (a compound chemical containing 4 quaternary ammoniums and 1 biguanide moiety). Eggs were sprayed according to treatment and allowed to dry for 1 h before sampling. To collect samples for the eggshell rinse, each egg was massaged in a plastic bag with 20 mL of saline. Eggshells were then aseptically opened and their contents were discarded before being individually crushed into 50-mL centrifuge tubes containing 20 mL of saline. Aerobic bacteria were enumerated on Petrifilm after 48 h of incubation at 37°C. Aerobic bacteria recovered (log(10) cfu/mL) from the eggshell rinse were highest and similar for the no-treatment (4.0) and water (3.7) groups, lower for the phenol (3.2) and H(2)O(2) (3.1) groups, and lowest for the Q(4)B (2.4) group. Aerobic bacteria levels with the crush-and-rub method were similar for the no-treatment (2.5) and water (2.3) groups, lower for the phenol (1.6) group, intermediate for the H(2)O(2) (1.2) group, and lowest for the Q(4)B (0.9) group. The overall correlation between the rinse and crush-and-rub sampling methods for individual egg aerobic bacteria counts was r = 0.71. The correlation within each treatment revealed the following r values: no treatment, 0.55; water, 0.72; H(2)O(2), 0.67; phenol, 0.73; and Q(4)B, 0.38. A second experiment was designed to further examine the lower aerobic bacterial levels recovered by the crush-and-rub method (for previously rinsed eggs) than the levels recovered in the initial eggshell rinse sample. Eggs were either rinsed and then crushed and rubbed, or they were only crushed and rubbed without a prior rinse. Results confirmed a significant decrease (1.5 log(10) cfu/mL) in bacteria levels between the initial rinse (4.4) and the subsequent crush and rub (2.9) for the same eggshell. For the crush-and-rub eggs with no previous rinsing, the bacteria recovery level (3.9) was not significantly different from levels for the rinse method. Therefore, either the rinse or crush-and-rub sampling methods can be used to recover similar levels of eggshell aerobic bacteria.
Poultry Science 07/2011; 90(7):1609-15. · 1.73 Impact Factor
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ABSTRACT: Retting, which is the microbial activity through which bast fibers are released from nonfiber tissues, is the limiting factor in flax processing. The objective of this work is to identify chemical and structural characteristics in a variety of fiber and seed flax types that influence enzyme retting in a recently developed method. Analyses of flax retted in a series of tests, including two enzyme rettings in some cases, indicated that lignin did not limit the separation of fibers from shive and showed that pectinases in enzyme-retting mixtures could ret fiber and seed flax. However, mature stems, such as that in flax produced for seed, had greater amounts of cutin and wax in the cleaned fiber product, suggesting that the cuticle could be a greater antiquality factor in seed versus fiber flax. With seed flax, the fraction of finer fibers produced during retting was significantly lower than with fiber flax. Results indicated that enzyme retting could be used to obtain flax fibers from seed flax stem residues and add value to this agricultural material.
Journal of Agricultural and Food Chemistry 01/2002; 49(12):5778-84. · 2.82 Impact Factor
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ABSTRACT: Seven strains of filamentous fungi and one yeast were isolated from flax that was dew retted in the United States. These filamentous fungi were subcultured to purity and identified, and six appear not to have been reported earlier as isolates from dew-retted flax. Five of the purified U.S. strains, two fungi isolated from flax that was dew retted in Europe, and a laboratory culture of Aspergillus sojae were tested for their ability to ret flax stems. The monocultures were evaluated for the degree of retting, fiber strength, dry weight loss, and tactile response (i.e., feel of softness) as reflected in the retted fiber. Structural modifications of representative samples of the retted flax were assessed by scanning electron microscopy. All of the filamentous fungi were able to carry out some retting, whereas the isolated yeast could not. All organisms produced pectinases when they were cultivated in shake flasks on ball-milled flax as the sole carbon source. Some fungi also produced cellulases, mannanases, and xylanases. Rhizomucor pusillus and Fusarium lateritium were noteworthy as retting organisms by their high level of pectinase activity, ability to attack noncellulosic cell types without attacking cellulose, capacity to penetrate the cuticular surface of the stem, and efficient fiber release from the core. The results indicated that these organisms deserve further study as potential organisms for retting of bast fibers in industrial applications.
Applied and Environmental Microbiology 11/1997; 63(10):3950-6. · 3.83 Impact Factor
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ABSTRACT: The white rot fungi Ceriporiopsis subvermispora FP-90031-sp and Cyathus stercoreus ATCC 36910 were evaluated for their ability to delignify Bermuda grass (Cynodon dactylon) stems and improve biodegradability. Compositional and structural alterations in plant cell walls effected by the fungi were determined by nuclear magnetic resonance spectroscopy, gas chromatography of alkali-treated residues, microspectrophotometry, and electron microscopy. Contaminating bacteria and fungi, which grew from unsterilized Bermuda grass stems, did not alter the improvement in grass biodegradability by either of the fungi from that of gas-sterilized stems. The biodegradation of stems by ruminal microorganisms, after treatment for 6 weeks with C. subvermispora or C. stercoreus, was improved by 29 to 32% and by 63 to 77%, respectively; dry weight losses caused by pretreatment with the fungi were about 20% over that in untreated, control stems. Both fungi preferentially removed aromatics to carbohydrates, and C. subvermispora removed proportionately more guaiacyl units than did C. stercoreus. Substantial amounts of ester-linked p-coumaric and ferulic acids were removed by both fungi, and about 23 and 41% of total aromatics (determined after 4 M NaOH direct treatment) were removed from the plant biomass after incubation with C. subvermispora and C. stercoreus, respectively. UV absorption microspectrophotometry indicated that ester-linked phenolic acids were totally removed from the parenchyma cell walls, and these cells were readily and completely degraded by both fungi. However, aromatic constituents were only partially removed from the more recalcitrant sclerenchyma cell walls, resulting in variation in electron density and random digestion pits after incubation with fiber-degrading bacteria.(ABSTRACT TRUNCATED AT 250 WORDS)
Applied and Environmental Microbiology 05/1995; 61(4):1591-8. · 3.83 Impact Factor
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ABSTRACT: Growth of the ruminal bacteria Ruminococcus flavefaciens FD1, Selenomonas ruminantium HD4, and Butyrivibrio fibrisolvens 49 was limited by ester-linked feruloyl and p-coumaroyl groups. The limitation of growth on phenolic acid-carbohydrate complexes varied with individual bacteria and appeared to be influenced by ability to hydrolyze carbohydrate linkages.
Applied and Environmental Microbiology 03/1993; 59(2):644-7. · 3.83 Impact Factor
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ABSTRACT: Ruminal bacteria from axenic cultures of Ruminococcus flavefaciens FD1, Butyrivibrio fibrisolvens 49, and bacterial types from the ruminal ecosystem that were fixed with 50 mM lysine (l-lysine hydrochloride) added to glutaraldehyde had better-preserved capsules and extracellular material than bacteria fixed without lysine.
Applied and Environmental Microbiology 10/1990; 56(9):2933-5. · 3.83 Impact Factor
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ABSTRACT: Ruminal bacteria or fungi were selected by the addition of cycloheximide or streptomycin and penicillin, respectively, to ruminal fluid, and the weakening and degradation of lignified tissues in alfalfa and Bermuda grass stems by these treatments and whole ruminal fluid were evaluated in vitro. Dry weight loss in alfalfa was similar for whole ruminal fluid and streptomycin-penicillin treatment, whereas that with streptomycin-penicillin treatment was significantly higher (P </= 0.05) than that with cycloheximide treatment. In Bermuda grass, dry weight loss was significantly higher with streptomycin-penicillin than that with whole ruminal fluid and cycloheximide treatment, which were equal. Both peak load (Newtons) and peak stress were less (P </= 0.05) for streptomycin-penicillin treatment than with other treatments in both forages. Fungi colonized the lignified ring in alfalfa and tended to reduce the width of cell walls in this tissue, but a large number of fungal penetrations through cell walls was not observed. In contrast, fungal rhizoids frequently penetrated into and through cell walls in the lignified ring of Bermuda grass, often expanding the pit fields between the cells. Ruminal fungi disrupt lignified tissues in stems, and their activity results in a weakened residue more amendable to physical degradation. This weakening may allow plant digesta to be more easily broken apart during animal's rumination and thus facilitate digesta flow and fiber utilization.
Applied and Environmental Microbiology 03/1989; 55(3):611-6. · 3.83 Impact Factor
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ABSTRACT: Anaerobic fungi in ruminal fluid from cows eating Bermuda grass hay plus a grain and minerals supplement were evaluated for diversity in sporangial morphotypes and colony growth patterns and for the degradation of various lignocelluloses. In selective cultures containing streptomycin and penicillin, an active population of ruminal fungi colonized leaf blades and degraded fiber at rates and extents almost equal to that of the total ruminal population. Three major sporangial morphotypes were consistently observed on leaf blades: oval, globose, and fusiform. Fungal colonies representing three distinct growth types consistently developed in anaerobic roll tubes inoculated with strained ruminal fluid. Sporangial morphotypes could not be matched to colony types due to multiple sporangial forms within a colony. Under identical growth conditions, one type exhibited a monocentric growth pattern, while two types exhibited polycentric growth patterns previously unreported in ruminal fungi. Mixed ruminal fungi in selective cultures or in digesta taken directly from the rumen produced a massive clearing of the sclerenchyma. Quantitation of tissue areas in cross sections by light microscopic techniques showed that fungal incubations resulted in significant (P = 0.05) increases in sclerenchyma degradation compared to whole ruminal fluid incubations. The mestome cell wall was at times penetrated and partially degraded by fungi; the colonization was less frequent and to a lesser degree than with the sclerenchyma. Conversely, ruminal bacteria were not observed to degrade the mestome sheath. Phenolic monomers at 1 mM concentrations did not stimulate to a significant (P = 0.05) extent the dry weight loss or fungal colonization of leaf blades; at 10 mM concentrations cinnamic and benzoic acids were toxic to ruminal fungi.
Applied and Environmental Microbiology 10/1987; 53(9):1987-95. · 3.83 Impact Factor
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ABSTRACT: Retting, which is the microbial activity through which bast fibers are released from nonfiber tissues, is the limiting factor in flax processing. The objective of this work is to identify chemical and structural characteristics in a variety of fiber and seed flax types that influence enzyme retting in a recently developed method. Analyses of flax retted in a series of tests, including two enzyme rettings in some cases, indicated that lignin did not limit the separation of fibers from shive and showed that pectinases in enzyme-retting mixtures could ret fiber and seed flax. However, mature stems, such as that in flax produced for seed, had greater amounts of cutin and wax in the cleaned fiber product, suggesting that the cuticle could be a greater antiquality factor in seed versus fiber flax. With seed flax, the fraction of finer fibers produced during retting was significantly lower than with fiber flax. Results indicated that enzyme retting could be used to obtain flax fibers from seed flax stem residues and add value to this agricultural material.
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ABSTRACT: Enzyme-retting offers an alternative to the current method of dew-retting to extract fibers from flax (Linum usitatissimum L.). Additional steps could improve the efficiency of enzyme-retting and modify the properties of the resulting fibers. Samples of 'Ariane' flax, which were grown in South Carolina during the winter and harvested early for quality fiber or late for both fiber and seed, were presoaked with distilled water before enzyme-retting. Soaked, enzyme-retted, and air-dried fibers were compared with unsoaked, control samples for yield and properties, and the water extract (or a freeze-dried portion) was tested in various methods for its influence on enzyme-retting. Presoaking increased fine fiber yield in some cases, but fiber strength at times was reduced. Analyses of the freeze-dried residue from soaking showed a mixture of sugars (128.6 and 101 mg g-1 for early and late harvest, respectively) and aromatic components including p-coumaric and ferulic acids and guaiacyl and syringyl units (3.51 and 3.05 mg g-1 total aromatics for early and late harvest, respectively). Water extracts from presoaking treatments at 1.0-2.0% (w/v) were not inhibitory to the retting fungus Rhizopus oryzae sb or to Viscozyme used for enzyme-retting, based on the Fried test and enzyme activities. Turbidity tests showed slight growth inhibition for Eschericia coli and Streptococcus sp. in the presence of water extracts from early versus late harvest flax at 0.5% (w/v), with those from late harvest flax more inhibitory. Benefits on the efficiency of water presoaking prior to enzyme-retting were moderate and not uniform in this study, and modifications may depend upon particular flax harvests.
