J F Hannah

University of Georgia, Athens, GA, United States

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Publications (9)8.02 Total impact

  • [Show abstract] [Hide abstract]
    ABSTRACT: This study was conducted to evaluate the influence of a vancomycin pretreatment on the ability of marker (nalidixic-acid resistant) Salmonella Enteritidis (SE(M)), field Salmonella Enteritidis (SE(E)), and marker Salmonella Typhimurium (ST(M)) strains to colonize within the intestinal and reproductive tracts and translocate to other organs of leghorn laying hens. In each of three trials, caged laying hens (76, 26, and 33 wk ofage) were divided into six groups designated to receive SE(M), SE(F), or ST(M), and half were pretreated with vancomycin (n = 11-12 hens). Vancomycin-treated hens received 10 mg vancomycin in saline/kilogram body weight orally for 5 days to inhibit Gram-positive bacteria within the intestines. On Day 6, all hens were concurrently challenged by oral, intravaginal, and intracolonal routes with Salmonella and placed into separate floor chambers by Salmonella strain. Two weeks postinoculation, all hens were euthanatized and the ceca, spleen, liver/gall bladder (LGB), upper (URT), and lower (LRT) reproductive tracts, and ovarian follicles were aseptically collected, and analyzed for Salmonella. Results did not differ for the three hen's ages and were therefore combined. The vancomycin pretreatment also had no significant effect on the colonization ability of SE(M), SE(F) or ST(M), and therefore results were combined within Salmonella strain. The marker strain of Salmonella Enteritidis was recovered from 21% of ceca, 4% of LGB, 9% of LRT, and 17% of the fecal samples. The field strain of Salmonella Enteritidis was recovered from 88% of ceca, 96% of spleen, 92% of LGB, 30% of LRT, 4% of URT, 13% of follicle, and 42% of the fecal samples. The marker strain of Salmonella Typhimurium was recovered from 100% of ceca, 74% of spleen, 91% of LGB, 30% of LRT, 9% of URT, 9% of follicle, and 100% of the fecal samples. Among ceca, spleen, LGB, and fecal samples, SE(F) and ST(M) colonization was significantly greater than SE(M) colonization. Overall prevalence of Salmonella in the reproductive tracts of challenged hens was relatively low, ranging from 4% to 30%.
    Avian Diseases 12/2011; 55(4):588-92. · 1.73 Impact Factor
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    ABSTRACT: In each of five sequential trials, laying hens (56-72 wk of age) were challenged with Salmonella and Campylobacter, and 1 wk postinoculation, the challenged hens (n = 3) were commingled with nonchallenged hens (n = 12) in conventional wire cages, on all-wire slats, or on all-shavings floor housing systems. After 12 days, challenged and nonchallenged hens were euthanatized for sample collection. Ceca were aseptically collected from all hens, and the spleen, liver/gallbladder (LGB), lower (LRT) and upper (URT) reproductive tracts, and ovarian follicles (mature and immature) were collected from only the challenged hens after commingling. Samples were divided equally and cultured separately for Salmonella and Campylobacter. Differences in the horizontal transmission of the challenge Salmonella to nonchallenged hens housed in cages (12%), on slats (15%), and on shavings (14%) were not significantly different (P > 0.05) from the challenged pen-mate hens over the five trials. However, with the inclusion of residual environmental Salmonella, the recovery of Salmonella from nonchallenged hens housed in cages was lowest at 15%, intermediate for hens on slats at 20%, and highest for hens on shavings at 38%. Among challenged hens housed in cages, Salmonella was recovered from only 27% of the cecum and LRT samples. From challenged hens housed on slats, Salmonella was recovered from 38% of the cecum, 12% of the spleen, 19% of the LGB, 44% of the LRT, and 19% of the URT samples. From challenged hens housed on shavings, Salmonella was recovered from 31% of the cecum; 15% of the spleen, LGB, and URT; and 31% of the LRT samples. Horizontal transmission of Campylobacter among nonchallenged pen-mate hens was significantly lower for hens housed in cages at 28% than for hens on shavings at 47%, with hens on slats being intermediate at 36%. For challenged hens housed in cages, Campylobacter was recovered from 27% of the cecum, 13% of the LRT, 7% of the URT, and 17% of the follicle samples. Among the challenged hens housed on slats, Campylobacter was recovered from 44% of the cecum, 6% of the spleen, 19% of the LGB, 12% of the LRT, 6% of the URT, and 14% of the follicle samples. Among challenged hens housed on shavings, Campylobacter was recovered from 46% of the cecum, 8% of the LRT and URT, and 40% of the follicle samples. The overall results of this study indicate that the caged housing system provided the lowest horizontal transmission level of Salmonella and Campylobacter among egg-laying hens.
    Avian Diseases 12/2011; 55(4):580-7. · 1.73 Impact Factor
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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. · 1.52 Impact Factor
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    ABSTRACT: Stomaching of skin samples releases only slightly more bacteria than a single rinse. Successive rinses, however, continue to remove almost as many bacteria as the first rinse. One hypothesis to explain this observation is that relatively violent treatment of skin generates smaller pieces of skin, thus increasing the net surface area and effectively sequestering bacteria in a water film on the skin pieces so that numbers of bacteria suspended in the rinsate do not increase. An experiment was conducted to determine whether inoculated marker bacteria are removed from the rinse liquid as skin pieces are stomached and naturally occurring bacteria are released. In each of 4 replications, 5 prechill broiler carcasses were collected from a commercial processing plant. Two 5-g pieces (n = 40) of breast skin were removed from each carcass and placed in a stomacher bag. An inoculum of 30 mL of 0.85% saline solution containing approximately 10(4) of nalidixic acid-resistant Salmonella enterica serovar Typhimurium per milliliter was added to each sample. Skin samples were hand-massaged for 30 s to mix the inoculum, after which a 1-mL aliquot was removed for enumeration of bacteria. A similar sample was taken after 4 min of vigorous stomaching of the skin sample. Bacterial counts recovered from the 30-s hand-massage were 4.3, 2.7, 2.6, and 3.7 log(10) cfu/mL of rinsate for aerobic bacteria, coliforms, Escherichia coli, and Salmonella, respectively. After stomaching, counts were 4.3, 2.9, 2.8, and 3.8, respectively. There was no difference in aerobic plate counts, but mean coliform and E. coli counts were significantly higher (P < 0.05) after stomaching. Numbers of inoculated Salmonella did not decrease. Breaking up the skin into smaller pieces by stomaching did not reduce the number of inoculated bacteria suspended in the rinsate.
    Poultry Science 02/2011; 90(2):491-3. · 1.52 Impact Factor
  • Journal of Applied Poultry Research - J APPL POULTRY RES. 01/2009; 18(2):252-258.
  • Journal of Applied Poultry Research - J APPL POULTRY RES. 01/2008; 17(2):272-277.
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    ABSTRACT: Experiments were conducted to evaluate a scraping method for enumerating bacteria on broiler carcasses. In experiment 1, coliforms and Escherichia coli were determined by the whole-carcass rinse (WCR) method and by scraping the skin surface and rinsing the blade (BR). In each of 2 replicate trials, 4 prechill broiler carcasses were collected from 2 different commercial processing plants. The WCR method was conducted on each carcass, then a blunt edge blade was used to scrape an area measuring approximately 80 cm(2) of the breast (front) skin and on the back of the carcass. After scraping, each blade and adhering residue was rinsed in 30 mL of 0.1% peptone. One milliliter of rinsate each from the WCR and BR was plated to determine total coliforms and E. coli. In experiment 2, 6 carcasses were collected from a processing plant in each of 2 replicate trials. Carcasses were split, with one half scraped on all skin surfaces, and the other half remaining unscraped as a control; all halves were then subjected to half-carcass rinses using 200 mL of 0.1% peptone. Coliforms and E. coli were enumerated. Results from both experiments are reported as log cfu/mL. In experiment 1, mean coliform WCR counts (5.1) were significantly higher (P < 0.05) than back BR (2.8), which were higher than front BR (2.2). Mean E. coli WCR counts (4.5) were higher than back BR (2.4), which were higher than front BR (1.6). The counts for BR adjusted for the greater surface area sampled by WCR were still lower than the WCR counts. Experiment 2 results showed no difference between control and scraped carcass halves for coliforms (4.7) or E. coli (4.6). Overall, results showed that scraping either prior to or after rinsing did not increase enumeration of coliforms or E. coli. Scraping could be a viable method to compare the numbers of bacteria on different areas of the same carcass.
    Poultry Science 08/2007; 86(7):1436-9. · 1.52 Impact Factor
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    ABSTRACT: An experiment was conducted to compare the whole carcass rinse method (WCR) versus scraping the breast skin or back skin for enumeration of total coliforms and E. coli. In each of two replicate trials, four pre-chill broiler carcasses were collected from two different commercial processing plants. WCR was conducted on each carcass using 400 mL 1% peptone and 1 min of shaking. After the WCR, a blunt edge stainless steel blade was used to scrape an area measuring approximately 80 square cm of the breast (front) skin. A similar area was scraped on the back of the carcass. After scraping, the blades were placed in plastic tubes and vigorously shaken for 3 sec in 30 mL 1% peptone. One mL of rinsate from the WCR and each scrape blade tube was plated to determine total coliforms and E. coli. Results are reported as log cfu/mL. Mean total coliform WCR counts (5.1) were significantly higher (P<0.05) than back scrapes (2.8), which were higher than front scrapes (2.2). Mean E. coli WCR counts (4.5) were higher than back scrapes (2.4), which were higher than front scrapes (1.6). There were no significant differences in counts due to the plant of origin. WCR counts were higher than scrape counts due to the difference in surface area sampled. When adjusted for surface area, mean total coliform back scrape count was 4.2, compared to WCR count of 5.1. Higher back scraping counts (vs. front) suggest that either more total bacteria are present on the back of the carcass or more bacteria on the back are loosened and recovered after scraping.
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    ABSTRACT: The objective of the experiments was to evaluate the bacteria levels of non-washed and washed eggs obtained from caged and cage-free laying hens housed on either all shavings or all wire slat floors. From 22 to 52 weeks-of-age (at 4 week intervals), 20 eggs were collected from each pen and 10 eggs/pen were washed for 1 min with a commercial egg washing solution (50 C, pH 11), while the remaining 10 eggs were not washed prior to sampling the eggshell and membranes (crush-and-rub) for aerobic bacteria (APC) and coliforms. Non-washed eggs produced in an all shavings environment had slightly higher bacteria numbers (APC 4.0 and coliforms 1.1 log10cfu/mL of rinsate) than eggs produced on slats (APC 3.6 and coliforms 1.0 log10cfu/mL of rinsate), which had significantly higher bacteria numbers than eggs produced in cages (APC 3.1 and coliforms 0.9 log10cfu/mL of rinsate). Washing significantly reduced APC by 1.8 log10cfu/mL (49%), reduced coliform counts by only 0.5 log10cfu/mL and coliform prevalence was reduced from 22.5, 17.5, 12.5% (shavings, slats, and cages, respectively) to 6%. No significant differences were found in APC and coliform counts on eggs from the three housing types following washing. When all hens were relocated into 2-hen triple deck cages in a separate room, eggshell APC levels (from 57 to 61 weeks-of-age) for non-washed eggs was 0.7 log10cfu/mL and for washed eggs was 0.1 log10cfu/mL, a 89% reduction. Housing hens in cage units with manure 2 removal and the absence of litter resulted in lower eggshell APC levels for both non-washed (by 2 log10cfu/mL) and washed eggs (by 1 log10cfu/mL).

Publication Stats

6 Citations
8.02 Total Impact Points

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Institutions

  • 2011
    • University of Georgia
      • Department of Poultry Science
      Athens, GA, United States
  • 2007
    • United States Department of Agriculture
      • Agricultural Research Service (ARS)
      Washington, D. C., DC, United States