@article{payne_li_santos_williams_sheldon_2011, title={Survey of Salmonella populations from swine waste-treatment technologies}, volume={19}, number={2}, journal={Journal of Swine Health and Production}, author={Payne, J. B. and Li, X. and Santos, F. B. O. and Williams, M. and Sheldon, B. W.}, year={2011}, pages={100–106} }
 @article{wang_oviedo-rondon_small_liu_sheldon_havenstein_williams_2010, title={Farm-Scale Evaluation of Ozonation for Mitigating Ammonia Concentrations in Broiler Houses}, volume={60}, ISSN={["2162-2906"]}, url={http://www.scopus.com/inward/record.url?eid=2-s2.0-77955613072&partnerID=MN8TOARS}, DOI={10.3155/1047-3289.60.7.789}, abstractNote={Abstract This study evaluated the effectiveness of in-house ozonation within the public health standard limit (0.1 parts per million [ppm]) for mitigating ammonia (NH3) concentrations inside commercial broiler houses. The project was conducted in four identical tunnel-ventilated houses. Two houses served as treatment and the other two served as control units. The experiment was replicated in five consecutive flocks. Except for ozonation treatment, all other operational parameters including feed, broiler strain, age and number of broilers, and ventilation system were the same among four houses. NH3 and carbon dioxide (CO2) concentrations in the treatment and control houses were measured for a minimum of 48 hr/week throughout the five flocks of 8 or 9 weeks each. The gas measurements were conducted using portable multigas units (PMUs). House temperatures were recorded with data loggers in each flock. Comparison of temperatures and CO2 concentrations among houses indicated no significant differences in ventilation rates among treatment and control houses in any of the five flocks. As a result, comparisons of NH3 concentrations inside houses were used to evaluate the effectiveness of house ozonation for NH3 emission mitigation. Statistical test of mean NH3 concentrations for each flock separated by house indicated that the house-to-house variation was significantly smaller than the flock-to-flock variation. There was a substantial variation in NH3 concentrations across different flocks, but no house had consistently higher or lower mean NH3 concentrations than any other. Evaluations for differences in mean NH3 from week to week, between treatment groups, and differences in week-to-week variations between treatment groups suggested that ozone effect was not uniform for each week and the effect was not statistically significant for any week. Tests of overall ozone treatment effect and treatment-week interaction indicated there was no difference in mean NH3 between the control and ozone treatment groups (P = 0.25), nor was the week effect different for control and treatment groups (P = 0.46). The results of this field evaluation indicate that there was no statistical evidence to suggest that the ozone treatment has any effect on average NH3 concentrations in these chicken houses.}, number={7}, journal={JOURNAL OF THE AIR & WASTE MANAGEMENT ASSOCIATION}, author={Wang, Lingjuan and Oviedo-Rondon, Edgar O. and Small, John and Liu, Zifei and Sheldon, Brian W. and Havenstein, Gerald B. and Williams, C. Mike}, year={2010}, month={Jul}, pages={789–796} }
 @article{rahimi_grimes_fletcher_oviedo_sheldon_2009, title={Effect of a direct-fed microbial (Primalac) on structure and ultrastructure of small intestine in turkey poults}, volume={88}, ISSN={0032-5791 1525-3171}, url={http://dx.doi.org/10.3382/ps.2008-00272}, DOI={10.3382/ps.2008-00272}, abstractNote={The effects of dietary supplementation of the direct-fed microbial (DFM) Primalac in mash or crumbled feed on histological and ultrastructural changes of intestinal mucosa was determined in 2 populations of poults; 1 with and 1 without a Salmonella spp. challenge. Three hundred thirty-six 1-d-old female Large White turkey poults were randomly distributed into 8 treatment groups with 6 replicates of 7 poults in each pen. The poults were placed on 1 of 4 dietary treatments in a 2 x 2 x 2 factorial arrangement (mash or crumble feed, with or without DFM, not-challenged or challenged at 3 d of age). The DFM groups were fed a Primalac-supplemented diet from d 1 until the last day of the experiment (d 21). At 3 d of age, 50% of the poults were challenged with 1 mL of 10(10) cfu/ mL of Salmonella spp. (Salmonella enterica serovar Typhimurium, Salmonella Heidelberg, and Salmonella Kentucky) by oral gavage. The inoculated poults were housed in a separate room from nonchallenged controls. Feed and water were provided ad libitum for all birds. At d 21, 1 poult per pen (total of 6 poults per treatment) was randomly selected and killed humanely by cervical dislocation. After necropsy, the small intestine was removed, and tissue samples from duodenum, jejunum, and ileum were taken for light and electron microscopic evaluation. The DFM birds showed increased goblet cell (GC) numbers, total GC area, GC mean size, mucosal thickness, and a greater number of segmented filamentous bacteria compared with controls. Changes in intestinal morphology as observed in this study support the concept that poultry gut health and function, and ultimately bird performance, can be improved by dietary supplementation with DFM products such as Primalac as used in this study.}, number={3}, journal={Poultry Science}, publisher={Oxford University Press (OUP)}, author={Rahimi, S. and Grimes, J. L. and Fletcher, O. and Oviedo, E. and Sheldon, B. W.}, year={2009}, month={Mar}, pages={491–503} }
 @article{grimes_rahimi_oviedo_sheldon_santos_2008, title={Effects of a direct-fed microbial (Primalac) on turkey poult performance and susceptibility to oral Salmonella challenge}, volume={87}, ISSN={["1525-3171"]}, DOI={10.3382/ps.2008-00498}, abstractNote={A study was conducted to determine 1) the effect of a dietary direct-fed microbial (DFM) on turkey poult performance, 2) the effect of a DFM on a Salmonella challenge, and 3) the effect of feed processing on the efficacy of the dietary DFM. Day-of-hatch Large White female poults were placed in 2 rooms in 2 Petersime batteries per room. Twelve pens of 7 birds each were used in each battery (24 pens per room, 336 birds total). One of 4 dietary feed treatments was assigned to each pen (6 pens per room for each diet). One room housed non-Salmonella-challenged poults, and the other room housed poults challenged with a 1-mL oral gavage of Salmonella (10(10) cfu/mL). A single batch of starter ration was split into 4 parts and used to provide 4 dietary treatments: 1) mash feed with no DFM (M), 2) mash feed with DFM (Primalac; 0.9 kg/tonne of feed, MD), 3) pelleted (20-s steam conditioning at 80 degrees C) and crumbled feed with no DFM (C), and 4) pelleted and crumbled feed with DFM (CD). Feed and deionized, distilled water were provided ad libitum. Data were collected and analyzed separately for each room. Mortality was recorded for each pen on a daily basis and totaled by week and for the 3-wk period. Individual BW and feed consumption, by pen, were measured weekly. Weekly and cumulative BW gains and feed to gain ratios (F:G) were calculated. Liver, spleen, total and lower intestinal tract weights, intestinal length, and most-probable-number Salmonella populations were determined for one randomly selected bird per pen. Feeding processed feed resulted in improved BW and F:G. Feeding the DFM improved 3-wk cumulative F:G in birds not gavaged and reduced relative intestinal weight in birds gavaged. Salmonella populations were reduced 1 log by feeding DFM. Dietary DFM improved bird performance, reduced Salmonella populations, and was not affected by feed processing.}, number={7}, journal={POULTRY SCIENCE}, author={Grimes, J. L. and Rahimi, S. and Oviedo, E. and Sheldon, B. W. and Santos, F. B. O.}, year={2008}, month={Jul}, pages={1464–1470} }
 @article{santos_sheldon_santos_ferket_2008, title={Influence of housing system, grain type, and particle size on Salmonella colonization and shedding of broilers fed triticale or corn-soybean meal diets}, volume={87}, ISSN={["1525-3171"]}, DOI={10.3382/ps.2006-00417}, abstractNote={Salmonella colonization in poultry may be influenced by grain type and particle size. Broilers reared either in nonlitter cage-based housing or in a conventionally floored litter house from 0 to 42 d were assigned to 1 of 4 dietary treatments: 1) ground corn-soybean meal (C, 560 microm), 2) coarsely ground corn-soybean meal (CC, >1,700 microm), 3) ground triticale-soybean meal (T, 560 microm), or 4) whole triticale-soybean meal (WT). A 4-strain cocktail of Salmonella enterica was orally gavaged into each chick at placement. Growth performance, cecal and fecal Salmonella populations, gizzard and proventriculus pH, intestinal size, jejunum histomorphometry, and carcass yields were measured. Broilers responded differently to the dietary treatments according to the housing system used. At 42 d, birds reared on litter and fed ground grain had greater BW than those fed coarse grain (2.87 vs. 2.71 kg), whereas cage-reared broilers fed ground triticale were heavier than those fed corn (2.75 vs. 2.64 kg). Broilers raised on litter had a better feed conversion ratio than those raised in cages (1.71 vs. 1.81 g/g). Independent of the housing system, relative eviscerated carcass weights of birds fed T and C were heavier than those of CC- and WT-fed broilers (762 vs. 752 g/kg). Generally, the jejunum villus area and mucosal depth were larger, whereas the small intestine was lighter and shorter in broilers raised on litter. Relative gizzard weights of broilers raised on litter and fed the coarser diets were heavier than those of broilers reared in cages and fed finely ground diets. Feeding whole or coarsely ground grains decreased cecal Salmonella populations in 42-d-old broilers (3.8, 3.9, 4.4, and 4.4 log most probable number/g for CC, WT, C, and T, respectively). Additionally, 42-d-old broilers reared on litter had lower cecal Salmonella populations than those in cages (3.8 vs. 4.4 log most probable number/g). In conclusion, as a feed ingredient, triticale is a good alternative to corn, resulting in improved BW and reduced Salmonella colonization. Broilers raised on litter may have achieved lower cecal Salmonella populations than caged birds because access to litter may have modulated the intestinal microflora by increasing competitive exclusion microorganisms, which discouraged Salmonella colonization.}, number={3}, journal={POULTRY SCIENCE}, author={Santos, F. B. O. and Sheldon, B. W. and Santos, A. A., Jr. and Ferket, P. R.}, year={2008}, month={Mar}, pages={405–420} }
 @article{santos_sheldon_santos_ferket_lee_petroso_smith_2007, title={Determination of ileum microbial diversity of broilers fed triticale- or corn-based diets and colonized by Salmonella}, volume={16}, ISSN={["1537-0437"]}, DOI={10.3382/japr.2006-00105}, abstractNote={SUMMARY Diversity of the bacterial communities in the ileum of broilers was characterized using denaturing gradient gel electrophoresis. Denaturing gradient gel electrophoresis separation of polymerase chain reaction amplicons of the V2-V3 variable regions of the 16S rDNA is a common method to profile community diversity and has been used to assess the effects of diet and antibiotics on the ileal bacterial community of chickens. Broilers raised either on litter floor or in cage batteries were fed either a finely ground corn- (control), a finely ground triticale-, or a whole triticale-based diet from 0 to 42 d. Microbial DNA was extracted from the ileum content of 42-d-old broilers, and the 16S rDNA gene was amplified by polymerase chain reaction and the amplicons separated by denaturing gradient gel electrophoresis. Diversity indexes including richness, evenness, diversity, and pairwise similarity coefficients were calculated. Diversity indexes were related to the dietary treatments, housing designs, and to changes in Salmonella colonization of broiler ceca as characterized by the most probable number method. Higher microbial diversity indexes were observed among birds fed whole triticale-based diets and reared on litter floors. In contrast, finely ground grain treatments had lower diversity and higher Salmonella prevalence than the whole triticale treatment. The data indicated that combination of high dietary fiber content and increased coarseness of the diet by feeding whole triticale stimulated microbial community diversity and discouraged Salmonella colonization, perhaps through a competitive exclusion-type mechanism.}, number={4}, journal={JOURNAL OF APPLIED POULTRY RESEARCH}, author={Santos, F. B. O. and Sheldon, B. W. and Santos, A. A., Jr. and Ferket, P. R. and Lee, M. D. and Petroso, A. and Smith, D.}, year={2007}, pages={563–573} }
 @article{mangalassary_han_rieck_acton_jiang_sheldon_dawson_2007, title={Effect of combining nisin and/or lysozyme with in-package pasteurization on thermal inactivation of listeria monocytogenes in ready-to-eat turkey Bologna}, volume={70}, ISSN={["1944-9097"]}, DOI={10.4315/0362-028X-70.11.2503}, abstractNote={Achieving a targeted lethality with minimum exposure to heat and preservation of product quality during pasteurization is a challenge. The objective of this study was to evaluate the effect of nisin and/or lysozyme in combination with in-package pasteurization of a ready-to-eat low-fat turkey bologna on the inactivation of Listeria monocytogenes. Sterile bologna samples were initially treated with solutions of nisin (2 mg/ml = 5,000 AU/ml = 31.25 AU/cm2), lysozyme (10 mg/ml = 80 AU/ml = 0.5 AU/cm2), and a mixture of nisin and lysozyme (2 mg/ml nisin + 10 mg/ml lysozyme = 31.75 AU/cm2). Bologna surfaces were uniformly inoculated with a Listeria suspension resulting in a population of approximately 0.5 log CFU/cm2. Samples were vacuum packaged and subjected to heat treatment (60, 62.5, or 65 degrees C). Two nonlinear models (Weibull and log logistic) were used to analyze the data. From the model parameters, the time needed to achieve a 4-log reduction was calculated. The nisin-lysozyme combination and nisin treatments were effective in reducing the time required for 4-log reductions at 62.5 and 65 degrees C but not at 60 degrees C. At 62.5 degrees C, nisin-lysozyme-treated samples required 23% less time than did the control sample to achieve a 4-log reduction and 31% less time at 65 degrees C. Lysozyme alone did not enhance antilisterial activity with heat. Results from this study can be useful to the industry for developing an efficient intervention strategy against contamination of ready-to-eat meat products by L. monocytogenes.}, number={11}, journal={JOURNAL OF FOOD PROTECTION}, author={Mangalassary, Sunil and Han, Inyee and Rieck, James and Acton, James and Jiang, Xiuping and Sheldon, Brian and Dawson, Paul}, year={2007}, month={Nov}, pages={2503–2511} }
 @article{santos_d'souza_jaykus_ferket_sheldon_2007, title={Genotypes, serotypes, and antibiotic resistance profiles of Salmonella isolated from commercial North Carolina Turkey farms}, volume={70}, ISSN={["1944-9097"]}, DOI={10.4315/0362-028X-70.6.1328}, abstractNote={This study was designed to determine the serotypes, genotypes, and antibiotic resistance (AbR) patterns of 42 Salmonella isolates recovered from either fecal or litter samples of 12 commercial turkey farms across two seasons (summer and winter) and two ages (3 and 19 weeks). Isolates were serotyped on the basis of the Kauffmann-White scheme. Genotyping was done by restriction digestion of cDNA (XbaI) and subsequent pulsed-field gel electrophoresis (PFGE). The AbR was determined with Sensititre susceptibility plates. Serovar Kentucky was the most prevalent serotype (26%), followed by Senftenberg (19%), Muenster (17%), Mbandaka (10%), Javiana (7%), Hadar (5%), Heidelberg (5%), 8,(20):nonmotile (5%), Agona (2%), Infantis (2%), and 4,12:r:-(2%). Serovars Kentucky, Heidelberg, Hadar, and 8,(20):nonmotile were isolated only from the 19-week-old bird samples, whereas Senftenberg and Muenster were isolated only from the young birds (3 weeks old). Isolates within any one serotype showed minor PFGE banding pattern differences, but dendogram analysis indicated that sequence variability between serotypes was more significant than within serotypes. Isolates were resistant to tetracycline (86%), sulfisoxazole (71%), streptomycin (64%), gentamicin (41%), ampicillin (36%), kanamycin (26%), sulfamethoxazole-trimethoprim (7%), nalidixic acid (5%), cefoxitin (2%), and ceftiofur (2%). One isolate (Muenster) was resistant to nine antibiotics (2%), and the others were resistant to six (7%), five (12%), four (10%), three (21%), two (24%), and one (10%) antibiotic. Only two isolates (5%) were susceptible to all antibiotics tested. The AbR patterns were affected by age; on average, strains recovered from young birds were resistant to more than four drugs compared with fewer than three in older birds (P < 0.05). This study showed that Salmonella enterica subsp. enterica serotypes, genotypes and AbR patterns were affected by bird age but not by season or farm.}, number={6}, journal={JOURNAL OF FOOD PROTECTION}, author={Santos, F. B. O. and D'Souza, D. H. and Jaykus, L. and Ferket, P. R. and Sheldon, B. W.}, year={2007}, month={Jun}, pages={1328–1333} }
 @article{payne_osborne_jenkins_sheldon_2007, title={Modeling the growth and death kinetics of Salmonella in poultry litter as a function of pH and water activity}, volume={86}, ISSN={["1525-3171"]}, DOI={10.1093/ps/86.1.191}, abstractNote={Contaminated poultry litter, serving as a reservoir for Salmonella, can be linked to both food safety concerns when contaminated birds enter processing plants and environmental concerns when used as a fertilizer. Predictive modeling allows for the estimation of microbial growth or inactivation as a function of controlling environmental growth factors. A study was conducted to observe the combined effects of pH and water activity (A(w)) at a constant temperature on Salmonella populations in used turkey litter to predict microbial response over time. Litter, first pH-adjusted and then inoculated with a 3-strain Salmonella serovar cocktail to an initial concentration of approximately 10(7) cfu/g, was placed into individual sealed plastic containers with saturated salt solutions for controlling A(w). A balanced design including 3 A(w) values (0.84, 0.91, 0.96), 3 pH values (4, 7, 9), and a constant temperature of 30 degrees C was used, with litter samples periodically removed and analyzed for Salmonella populations, pH, and A(w). At each combination of environmental factors, the Churchill or exponential inactivation mathematical models were used to describe the growth and death of Salmonella over time. Salmonella populations exhibited growth (approximately 2 log) with little decline up to 42 d in litter environments of pH 7 and 9 and a A(w) of 0.96. As litter A(w) and pH levels were reduced, populations declined, with the most drastic reductions (approximately 5 log in 9 h) occurring in low-pH (4) and low-A(w) (0.84) environments. Generalized models for bacterial growth and death under grouped pH environments were successfully developed to predict Salmonella behavior in litter over time. These findings suggest that the best management practices and litter treatments that lower litter A(w) to < or =0.84 and pH to < or =4 are effective in reducing Salmonella populations. The use of a single equation to predict the growth and decline of Salmonella populations as a function of pH and A(w) has potential application for use in the development of effective pathogen control strategies at the farm level.}, number={1}, journal={POULTRY SCIENCE}, author={Payne, J. B. and Osborne, J. A. and Jenkins, P. K. and Sheldon, B. W.}, year={2007}, month={Jan}, pages={191–201} }
 @article{li_payne_santos_levine_anderson_sheldon_2007, title={Salmonella Populations and Prevalence in Layer Feces from Commercial High-Rise Houses and Characterization of the Salmonella Isolates by Serotyping, Antibiotic Resistance Analysis, and Pulsed Field Gel Electrophoresis}, volume={86}, ISSN={0032-5791}, url={http://dx.doi.org/10.1093/ps/86.3.591}, DOI={10.1093/ps/86.3.591}, abstractNote={Salmonella species are recognized as a major cause of foodborne illnesses that are closely associated with the consumption of contaminated poultry and egg products. The objectives of this study were to evaluate the Salmonella populations and prevalence in layer feces during the laying cycle and molting of the hen and to characterize the layer fecal Salmonella isolates by serotyping, antibiotic resistance analysis, and pulsed field gel electrophoresis. Fecal samples were collected from a commercial layer complex consisting of 12 houses. Composite fecal samples across each row were collected as a function of bird age [18 wk (at placement), 25 to 28 wk (first peak of production cycle), 66 to 74 wk (molting), and 75 to 78 wk (second peak of production cycle)]. Bird ages and molting practice did not significantly affect (P > 0.05) Salmonella populations with an average of 1.25, 1.27, 1.20, and 1.14 log most probable number/g for the 18-, 25- to 28-, 66- to 74-, and 75- to 7-wk birds, respectively. However, the 18-wk birds had the highest prevalence of Salmonella (55.6%), followed by the 25- to 28-wk birds (41.7%), 75- to 78-wk birds (16.7%), and 66- to 74-wk birds (5.5%). Of the 45 Salmonella isolates characterized, the most predominant serovar was Salmonella Kentucky (62%). Thirty-five percent of the Salmonella isolates were resistant to at least 1 antibiotic. As expected, considerable genetic diversity was observed within and across the different serovars.}, number={3}, journal={Poultry Science}, publisher={Elsevier BV}, author={Li, X. and Payne, J.B. and Santos, F.B. and Levine, J.F. and Anderson, K.E. and Sheldon, B.W.}, year={2007}, month={Mar}, pages={591–597} }
 @article{ahlborn_clare_sheldon_kelly_2006, title={Identification of Eggshell Membrane Proteins and Purification of Ovotransferrin and β-NAGase from Hen Egg White}, volume={25}, ISSN={1572-3887 1573-4943}, url={http://dx.doi.org/10.1007/s10930-006-0010-8}, DOI={10.1007/s10930-006-0010-8}, abstractNote={Exposure of selected Gram-positive and Gram-negative bacterial pathogens to egg shell membranes (ESM) significantly reduced their thermal resistance and/or inactivated cells. Although the components responsible for this antibacterial activity have not been conclusively identified, several proteins associated with the ESM activity have been identified including beta-N-acetylglucosaminidase, lysozyme and ovotransferrin, with each displaying varying degrees of antibacterial activity. Numerous attempts to purify active fractions of beta-N-acetylglucosaminidase, lysozyme and ovotransferrin from the ESM proved somewhat limited; however, hen egg white (HEW) beta-N-acetylglucosaminidase was purified using a two-step chromatographic procedure, isoelectric focusing followed by cation exchange chromatography. Pure fractions of ovotransferrin were also obtained in the process. SDS-PAGE electrophoresis and Matrix-Assisted Laser Desorption Time-of-Flight Mass Spectrometry were then used to partially characterize the individual protein components. Purified protein fractions such as these will be required in order to fully elucidate the mechanism responsible for the antimicrobial properties associated with the ESM.}, number={1}, journal={The Protein Journal}, publisher={Springer Science and Business Media LLC}, author={Ahlborn, G. J. and Clare, D. A. and Sheldon, B. W. and Kelly, R. W.}, year={2006}, month={Jan}, pages={71–81} }
 @article{ahlborn_sheldon_2006, title={Identifying the components in eggshell membrane responsible for reducing the heat resistance of bacterial pathogens}, volume={69}, ISSN={["1944-9097"]}, DOI={10.4315/0362-028x-69.4.729}, abstractNote={The biological activity (D-value determination) of eggshell membrane (ESM) was examined to determine the membrane components and mechanisms responsible for antibacterial activity. Biological and enzymatic activities (i.e., beta-N-acetylglucosaminidase [beta-NAGase], lysozyme, and ovotransferrin) of ESM denatured with trypsin, lipases, or heat were compared with those of untreated ESM. Trypsin-treated ESM lost all biological activity (D-values at 54 degrees C were 5.12 and 5.38 min for immobilized and solubilized trypsin, respectively) but showed no significant loss of enzymatic activities. Treatments with porcine lipase and a lipase cocktail did not impact biological or enzymatic activities. Heat denaturation of ESM (at 80 and 100 degrees C for 15 min) resulted in significant decreases in biological activity (D-values of 3.99 and 4.43 min, respectively) and loss of beta-NAGase activity. Lysozyme and ovotransferrin activities remained but were significantly reduced. Purified ESM and hen egg white components (i.e., beta-NAGase, lysozyme, and ovotransferrin) were added to Salmonella Typhimurium suspensions (in 0.1% peptone water) at varying concentrations to evaluate their biological activity. D-values at 54 degrees C were 4.50 and 3.68 min for treatment with lysozyme or beta-NAGase alone, respectively, and 2.44 min for ovotransferrin but 1.47 min for a combination of all three components (similar to values for ESM). Exposure of Salmonella Typhimurium cells to a mixture of ovotransferrin, lysozyme, and beta-NAGase or ESM resulted in significant increases in extracellular concentrations of Ca2+, Mg2+, and K+. Transmission electron microscopic examination of Salmonella Typhimurium cells treated with a combination of ovotransferrin, lysozyme, and beta-NAGase revealed membrane disruption and cell lysis. The findings of this study demonstrate that ovotransferrin, lysozyme, and beta-NAGase are the primary components responsible for ESM antibacterial activity. The combination of these proteins and perhaps other ESM components interferes with interactions between bacterial lipopolysaccharides, sensitizing the outer bacterial membrane to the lethal affects of heat and possibly pressure and osmotic stressors.}, number={4}, journal={JOURNAL OF FOOD PROTECTION}, author={Ahlborn, G and Sheldon, BW}, year={2006}, month={Apr}, pages={729–738} }
 @article{ahlborn_sheldon_2005, title={Enzymatic and microbiological inhibitory activity in eggshell membranes as influenced by layer strains and age and storage variables}, volume={84}, ISSN={["1525-3171"]}, DOI={10.1093/ps/84.12.1935}, abstractNote={Eggshell membranes (ESM) have been shown to exhibit antibacterial activity. The purpose of this study was to evaluate the enzymatic and biological [decimal reduction times (D-values)] activities of ESM as a function of bird breed, age, and ESM stabilization treatments. Younger White Leghorn (WL) hens produced ESM with 28% higher lysozyme activity than Rhode Island Red (RIR) layers. In contrast, older WL layers produced ESM with 17% less lysozyme activity than ESM from RIR layers. Similarly, beta-N-acetylglucosaminidase (beta-NAGase) ESM activities differed by hen age within breeds with younger hens yielding 14 to 16% more enzyme activity. D54 degrees C-values of Salmonella Typhimurium cells preexposed to WL ESM did not differ as a function of bird age (33, 50, and 81 wk). The ESM Lysozyme and beta-NAGase activities varied somewhat over a 6-mo storage study after treatment with 1 of 5 stabilization methods [i.e., storage at 4 degrees C, -20 degrees C, or ambient air storage after freeze drying, air drying (23 degrees C), or forced-air drying (50 degrees C)]. Both air and forced-air drying yielded significant reductions in beta-NAGase and lysozyme ESM activity (ca 12 to 30%) after the initial 24 h and then remained fairly stable during the extended storage. Freeze-dried samples retained the most enzymatic activity (95%) throughout the 6-mo trial, whereas refrigerated ESM lost 20 and 18% of the beta-NAGase and lysozyme activities, respectively. Frozen ESM lost 22% of the beta-NAGase activity, whereas lysozyme was nearly unaffected after 6 mo. The ESM biological activities against S. Typhimurium were not adversely impacted by layer breed or age. No significant loss in biological activity of ESM was detected 24 h after processing or after 6 mo of storage for refrigerated, frozen, and freeze-dried membranes, whereas significant reductions were observed for air- and heat-dried ESM. These findings demonstrate that ESM enzyme and biological activities are relatively constant across layer breeds and over extended storage. Based on these and other findings, ESM may have potential commercial value as a processing adjuvant in food and pharmaceutical product applications.}, number={12}, journal={POULTRY SCIENCE}, author={Ahlborn, G and Sheldon, BW}, year={2005}, month={Dec}, pages={1935–1941} }
 @article{santos_li_payne_sheldon_2005, title={Estimation of most probable number Salmonella populations on commercial North Carolina turkey farms}, volume={14}, ISSN={["1537-0437"]}, DOI={10.1093/japr/14.4.700}, abstractNote={Abstract Salmonellae are one of the primary causes of human gastroenteritis in the United States. Although there are many foods that may be contaminated with Salmonella, poultry products are one of the major vehicles for transmitting this organism to humans. However, the national incidence of poultry product contamination with Salmonella has declined since adoption of the Hazard Analysis and Critical Control Point (HACCP) food safety program. Further reductions in carcass contamination may require other approaches such as the adoption of on-farm pathogen reduction strategies. In this study Salmonella prevalence and populations from fresh excreta and litter composite samples taken from 12 commercial turkey farms were enumerated using the most probable number (MPN) method and compared as a function of farm, season (summer and winter), and bird age (3 vs. 19 wk). Moreover, litter pH, temperature, moisture content, water activity, and ammonia levels were monitored. All farms were Salmonella positive for at least one season, and populations ranged from 5.3 log MPN/g. Of the 48 separate fecal and litter composite samples analyzed, 70 and 79% were Salmonella-positive, respectively. Although the MPN enumeration method is much more labor intensive and costly than the prevalence method, it yields estimates of Salmonella populations instead of merely indications of presence or absence of the organism. Moreover, our findings demonstrated that the MPN method is significantly more sensitive compared with the prevalence procedure (for fecal samples). This study also demonstrated that Salmonella can be present at high populations during turkey production and that their populations and prevalence were significantly impacted by flock age (litter) and season by farm interactions (fecal). Furthermore, litter Salmonella populations appear to be associated with the interrelated parameters of litter pH, ammonia and moisture content.}, number={4}, journal={JOURNAL OF APPLIED POULTRY RESEARCH}, author={Santos, FBO and Li, X and Payne, JB and Sheldon, BW}, year={2005}, pages={700–708} }
 @article{mccormick_han_acton_sheldon_dawson_2005, title={In-package pasteurization combined with biocide-impregnated films to inhibit Listeria monocytogenes and Salmonella typhimurium in Turkey bologna}, volume={70}, ISSN={["1750-3841"]}, DOI={10.1111/j.1365-2621.2005.tb09046.x}, abstractNote={The inhibitory effects of in-package pasteurization (3-5D, decimal reduction times) combined with a nisin (7%, w/w) containing wheat gluten film were tested over an 8-wk storage period against Listeria monocytogenes and Salmonella Typhimurium populations inoculated on refrigerated bologna. Bologna slices subjected to the in-package pasteurization process reduced L. monocytogenes populations 3.8- to 7.0-log colony-forming units (CFU)/g, and the remaining population fluctuated between 1.2- and 3.8-log CFU/g over the 2-mo storage period. S. Typhimurium was reduced 5.7- to 7.3-log CFU/g, and the remaining population progressively declined from 100 to <10 CFU/g over 2 mo of storage. The wheat gluten film containing nisin was effective in reducing the population of L. monocytogenes (2.75-log reduction with pasteurization; 1-log reduction without pasteurization), but was not effective against S. Typhimurium (<1-log reduction). Combining both treatments significantly reduced the L. monocytogenes populations and prevented outgrowth over the 2-mo storage period but provided no added inhibitory effect against S. Typhimurium compared with only pasteurization.}, number={1}, journal={JOURNAL OF FOOD SCIENCE}, author={McCormick, KE and Han, IY and Acton, JC and Sheldon, BW and Dawson, PL}, year={2005}, pages={M52–M57} }
 @article{li_sheldon_ball_2005, title={Thermal resistance of Salmonella enterica serotypes, Listeria monocytogenes, and Staphylococcus aureus in high solids liquid egg mixes}, volume={68}, ISSN={["1944-9097"]}, DOI={10.4315/0362-028X-68.4.703}, abstractNote={Decimal reduction times (D-values) were determined for Salmonella enterica serotypes, Listeria monocytogenes, and Staphylococcus aureus in two high solids egg mixes designated A and B (water activity [a(w)] = 0.76 and 0.82; solids = 53.12 and 52.63%; pH = 5.09 and 5.29; viscosity = 183 and 119 centipoise/s, respectively) using a low-volume (0.06 ml) sealed glass capillary tube procedure. For Salmonella, D-values ranged from 0.035 (70 degrees C) to 0.193 min (64 degrees C) in product A and from 0.048 to 0.193 min in product B. For Listeria, D-values ranged from 0.133 (70 degrees C) to 0.440 min (64 degrees C) in product A and from 0.074 to 0.364 min in product B. For Staphylococcus, D-values ranged from 0.332 (70 degrees C) to 1.304 min (64 degrees C) in product A and from 0.428 to 1.768 min in product B. For Listeria, the D-values of all heating temperatures were significantly higher (P < 0.01) in product A than in product B. The similar trend was also observed for Salmonella and Staphylococcus but only at 66 degrees C for Salmonella and 64 degrees C for Staphylococcus. Greater temperature dependence was observed for Salmonella inactivation in the low a(w) and low pH product (A), while the product (B) with the higher a(w) and pH had greater temperature dependence for Listeria. Compared across both egg mixes and all heating temperatures, the Staphylococcus strains were from 6.2 to 11.7 times more heat resistant than S. enterica serotypes and from 2.2 to 7.5 times more heat resistant than L. monocytogenes.}, number={4}, journal={JOURNAL OF FOOD PROTECTION}, author={Li, X and Sheldon, BW and Ball, HR}, year={2005}, month={Apr}, pages={703–710} }
 @misc{keener_bashor_curtis_sheldon_kathariou_2004, title={Comprehensive review of Campylobacter and poultry processing}, volume={3}, ISSN={["1541-4337"]}, DOI={10.1111/j.1541-4337.2004.tb00060.x}, abstractNote={ABSTRACT}, number={2}, journal={COMPREHENSIVE REVIEWS IN FOOD SCIENCE AND FOOD SAFETY}, author={Keener, KM and Bashor, MP and Curtis, PA and Sheldon, BW and Kathariou, S}, year={2004}, month={Apr}, pages={105–116} }
 @article{bashor_curtis_keener_sheldon_kathariou_osborne_2004, title={Effects of carcass washers on Campylobacter contamination in large broiler processing plants}, volume={83}, ISSN={["1525-3171"]}, DOI={10.1093/ps/83.7.1232}, abstractNote={Campylobacter, a major foodborne pathogen found in poultry products, remains a serious problem facing poultry processors. Campylobacter research has primarily focused on detection methods, prevalence, and detection on carcasses; limited research has been conducted on intervention. The aim of this study was to assess the effectiveness of carcass washing systems in 4 large broiler-processing plants in removing Campylobacter species. Washing systems evaluated included combinations of inside/outside carcass washers and homemade cabinet washers. Processing aids evaluated were trisodium phosphate (TSP) and acidified sodium chlorite (ASC). The washer systems consisted of 1 to 3 carcass washers and used from 2.16 to 9.73 L of water per carcass. The washer systems used chlorinated water with 25 to 35 ppm of total chlorine. These washer systems on average reduced Campylobacter populations by log 0.5 cfu/mL from log 4.8 cfu/mL to log 4.3 cfu/mL. Washer systems with TSP or ASC reduced Campylobacter populations on average by an additional log 1.03 to log 1.26, respectively. Total average reductions in Campylobacter populations across the washer system and chill tank were log 0.76 cfu/mL. Washer systems that included antimicrobial systems had total average reductions in Campylobacter populations of log 1.53 cfu/mL. These results suggest that carcass washer systems consisting of multiple washers provide minimal reductions in Campylobacter populations found on poultry in processing plants. A more effective treatment of reducing Campylobacter populations is ASC or TSP treatment; however, these reductions, although significant, will not eliminate the organism from raw poultry.}, number={7}, journal={POULTRY SCIENCE}, author={Bashor, MP and Curtis, PA and Keener, KM and Sheldon, BW and Kathariou, S and Osborne, JA}, year={2004}, month={Jul}, pages={1232–1239} }
 @article{mccormick_han_acton_sheldon_dawson_2003, title={D- and z-values for Listeria monocytogenes and Salmonella Typhimurium in packaged low-fat ready-to-eat turkey bologna subjected to a surface pasteurization treatment}, volume={82}, ISSN={["1525-3171"]}, DOI={10.1093/ps/82.8.1337}, abstractNote={The D-values of Listeria monocytogenes and Salmonella Typhimurium at various surface pasteurization temperatures were determined for low-fat turkey bologna. Four cm2 meat squares were sterilized by irradiation prior to inoculation with 0.1 mL of a 10(8) cfu/mL culture, aseptically packaged in a linear low-density polyethylene pouch, and vacuum-sealed. Thermal treatments were administered by submerging packages in a heated water bath maintained at various set temperatures. At an 85 degrees C water bath temperature, no L. monocytogenes cells were detected (<10(2)) after 10 s of exposure, whereas at 61 degrees C cells viable were detected (>10(2)) up to 10 min of heating. No S. Typhimurium cells (<10(2)) were detected after 10 s at 70 degrees C, but cells survived up to 7 min at 60 degrees C. The D-values for L. monocytogenes at 61 and 65 degrees C were 124 and 16.2 s, respectively; whereas S. Typhimurium D-values were 278 s at 57 and 81 s at 60 degrees C. Z-values were 4.44 and 5.56 degrees C, respectively, for L. monocytogenes and S. Typhimurium. This study demonstrated that significant reductions in bacterial populations and complete inactivation of S. Typhimurium and L. monocytogenes cells can be achieved using an in-package thermal pasteurization process.}, number={8}, journal={POULTRY SCIENCE}, author={McCormick, K and Han, IY and Acton, JC and Sheldon, BW and Dawson, PL}, year={2003}, month={Aug}, pages={1337–1342} }
 @article{moore_sheldon_2003, title={Evaluation of time-temperature integrators for tracking poultry product quality throughout the chill chain}, volume={66}, ISSN={["0362-028X"]}, DOI={10.4315/0362-028X-66.2.287}, abstractNote={The goal of this study was to evaluate the application of one type of time-temperature integrator (TTI) to monitor the microbiological quality of ice-packed raw chicken drumsticks as a function of temperature exposure. A kinetics-based model was used to correlate the TTI chroma response to the number of bacteria on the drumstick surface under constant- and variable-temperature conditions. Two constant-temperature studies (4 and 15 degrees C) and one variable-temperature study (4 degrees C for 24 h, 15 degrees C for 24 h, 4 degrees C constant) were conducted to evaluate the applicability of the TTI under ideal and worst-case situations. During the constant-temperature studies, quality predictions made at the midpoint of the product shelf life were accurate within 15% for the observed bacterial populations. The accuracy of the TTI was marginal in the initial and final stages of the response period. During the variable-temperature study, the TTI response demonstrated positive history effects, whereby the observed rate constant is affected by previous temperature exposure. After the TTIs had been held at 15 degrees C for 24 h, the TTI response rate constant observed during subsequent storage at 4 degrees C was higher than what would be predicted for 4 degrees C. Further work will be needed to develop a continuous TTI-based quality monitoring system. However, because the microbiological quality of fresh poultry could be reliably predicted with kinetic models, fresh poultry products would be excellent candidates for a TTI-based quality monitoring system.}, number={2}, journal={JOURNAL OF FOOD PROTECTION}, author={Moore, CM and Sheldon, BW}, year={2003}, month={Feb}, pages={287–292} }
 @article{schuman_sheldon_2003, title={Inhibition of Listeria monocytogenes in pH-adjusted pasteurized liquid whole egg}, volume={66}, ISSN={["0362-028X"]}, DOI={10.4315/0362-028X-66.6.999}, abstractNote={Although the transmission of L. monocytogenes to humans via pasteurized egg products has not been documented, L. monocytogenes and other Listeria species have been isolated from commercially broken raw liquid whole egg (LWE) in both the United States and Ireland. Recent Listeria thermal inactivation studies indicate that conventional minimal egg pasteurization processes would effect only a 2.1- to 2.7-order-of-magnitude inactivation of L. monocytogenes in LWE; thus, the margin of safety provided by conventional pasteurization processes is substantially smaller for L. monocytogenes than for Salmonella species (a 9-order-of-magnitude process). The objective of this study was to evaluate the inhibitory effects of nisin on the survival and growth of L. monocytogenes in refrigerated and pH-adjusted (pH 6.6 versus pH 7.5) ultrapasteurized LWE and in a liquid model system. The addition of nisin (1,000 IU/ml) to pH-adjusted ultrapasteurized LWE reduced L. monocytogenes populations by 1.6 to > 3.3 log CFU/ml and delayed (pH 7.5) or prevented (pH 6.6) the growth of the pathogen for 8 to 12 weeks at 4 and 10 degrees C. Bioactive nisin was detected in LWE at both pH values for 12 weeks at 4 degrees C. In subsequent experiments, Listeria reductions of > 3.0 log CFU/ml were achieved within 24 h in both LWE and broth plus nisin (500 IU/ml) at pH 6.6 but not at pH 7.5, and antilisterial activity was enhanced when nisin was added as a solution rather than in dry form.}, number={6}, journal={JOURNAL OF FOOD PROTECTION}, author={Schuman, JD and Sheldon, BW}, year={2003}, month={Jun}, pages={999–1006} }
 @article{de cesare_sheldon_smith_jaykus_2003, title={Survival and persistence of Campylobacter and Salmonella species under various organic loads on food contact surfaces}, volume={66}, ISSN={["1944-9097"]}, DOI={10.4315/0362-028X-66.9.1587}, abstractNote={Although many cases of Campylobacter and Salmonella enteritis have been attributed to the undercooking of poultry and other foods, cross-contamination between raw and cooked foods via food contact surfaces and worker contact has also been identified as a significant risk factor. Cross-contamination may be particularly important in relation to the high prevalence of contamination in raw poultry products and other foods and the low infectious doses that have been reported for Campylobacter species. Lag phase and decimal reduction times (D-values at 27 degrees C [81 degrees F] and 60 to 62% relative humidity) were determined for Campylobacter jejuni and Salmonella species (five-strain pools) suspended in either a phosphate-buffered saline (PBS) solution or Trypticase soy broth (TSB) and then inoculated (0.1-ml drop per surface) on 5-cm2 samples of Formica laminate (F), glazed ceramic tile (CT), 304 polished stainless steel (SS), and 100% cotton dishcloth (D). Triplicate samples were collected from each contact surface periodically, and the populations of surviving organisms were enumerated on Campy Cefex and brain heart infusion agars for C. jejuni and Salmonella species, respectively. Lag time and rate of inactivation were influenced by organism type, contact surface, and suspending medium. Initial mean lag times ranging from 60 to 190 min were followed by log-linear (r2 > 0.94) decreases in cell populations that varied across contact surfaces. D-values of 12.5, 19.1, 24.1, and 29.7 min and of 23.7, 10.5, 12.7, and 13.9 min were calculated for C. jejuni suspended in PBS and TSB and then spotted on D, F, SS, and CT surfaces, respectively. The times required to produce a 3-log reduction in population with PBS and TSB ranged from 102 (D) to 247 (F) min and from 112 (CT) to 167 (F) min, respectively. C. jejuni cells suspended in the nutritionally enriched medium (TSB) and spotted on the hard surfaces were inactivated about 1.4 times as fast as cells suspended in PBS. For the Salmonella test strains, D-values of 17.1, 426.6, 118.6, and 41.9 min and of 48.2, 1363.2, 481.8, and 134.2 min were calculated for cells suspended in PBS and TSB and then spotted on D, E SS, and CT surfaces, respectively. In contrast to C. jejuni, Salmonella serotypes were 1.7 to 3.3 times more persistent when suspended in TSB than when suspended in PBS and were 1.2 to 25.3 times more persistent than C. jejuni, depending on the contact surface and the type of suspension fluid (i.e., overall time required to achieve a 3-log reduction in population, lag time + 3 x D). These findings indicate that both the contact surface and the level of organic matter can influence the survival and persistence of C. jejuni and Salmonella species on food contact surfaces.}, number={9}, journal={JOURNAL OF FOOD PROTECTION}, author={De Cesare, A and Sheldon, BW and Smith, KS and Jaykus, LA}, year={2003}, month={Sep}, pages={1587–1594} }
 @article{moore_sheldon_jaykus_2003, title={Transfer of Salmonella and Campylobacter from stainless steel to romaine lettuce}, volume={66}, ISSN={["1944-9097"]}, DOI={10.4315/0362-028X-66.12.2231}, abstractNote={The degree of transfer of Campylobacter jejuni and Salmonella enterica serovar Typhimurium was evaluated from a stainless steel contact surface to a ready-to-eat food (lettuce). Stainless steel coupons (25 cm2) were inoculated with a 20-microl drop of either C. jejuni or Salmonella Typhimurium to provide an inoculum level of approximately 10(6) CFU/28 mm2. Wet and dry lettuce (Lactuca sativa var. longifolia) pieces (9 cm2) were placed onto the inoculated stainless steel surface for 10 s after the designated inoculum drying time (0 to 80 min for C. jejuni; 0 to 120 min for Salmonella Typhimurium), which was followed by the recovery and enumeration of transferred pathogens (lettuce) and residual surface pathogens (stainless steel coupons). For transfers of Salmonella Typhimurium to dry lettuce, there was an increase from 36 to 66% in the percent transfer of the initial inoculum load during the first 60 min of sampling and then a precipitous drop from 66 to 6% in percent transfer. The transfer of Salmonella Typhimurium to wet lettuce ranged from 23 to 31%, with no statistically significant difference between recoveries over the entire 120-min sampling period. For C. jejuni, the mean percent transfer ranged from 16 to 38% for dry lettuce and from 15 to 27% for wet lettuce during the 80-min sampling period. The results of this study indicate that relatively high numbers of bacteria may be transferred to a food even 1 to 2 h after surface contamination. These findings can be used to support future projects aimed at estimating the degree of risk associated with poor handling practices of ready-to-eat foods.}, number={12}, journal={JOURNAL OF FOOD PROTECTION}, author={Moore, CM and Sheldon, BW and Jaykus, LA}, year={2003}, month={Dec}, pages={2231–2236} }
 @article{moore_sheldon_2003, title={Use of time-temperature integrators and predictive modeling to evaluate microbiological quality loss in poultry products}, volume={66}, ISSN={["0362-028X"]}, DOI={10.4315/0362-028X-66.2.280}, abstractNote={The purpose of this study was to characterize the kinetics of the spoilage process of chicken drumsticks in order to evaluate the application of an enzyme process-based time-temperature integrator (TTI) as a continuous quality monitor of poultry products. Shelf life studies were conducted at several temperatures (3 to 20 degrees C) to characterize (i) the poultry spoilage process as a function of total aerobic bacteria and Pseudomonas species populations and (ii) the TTI chroma response function. Two types of poultry products were examined: ice-packed and chill-packed drumsticks. An enzyme-based TTI with a color change response from green to yellow was used. Activation energies for each of the poultry products and each of the bacterial populations were as follows: 21.8 +/- 1.6 kcal/mol (ca. 91.2 +/- 6.7 kJ/mol) for ice-packed drumsticks and total aerobic population, 18.8 +/- 4.5 kcal/mol ca. 78.7 +/- 18.8 kJ/mol) for ice-packed drumsticks and Pseudomonas spp., 17.0 +/- 2.3 kcal/mol (ca. 71.1 +/- 9.6 kJ/mol) for chill-packed drumsticks and total aerobic population, and 14.1 +/- 3.6 kcal/mol (ca. 59.0 +/- 15.1 kJ/mol) for chill-packed drumsticks and Pseudomonas spp. The activation energy calculated for the TTI, 19.1 +/- 1.8 kcal/mol (ca. 79.9 +/- 7.5 kJ/mol), was determined to be adequately close to that of the poultry spoilage process to make effective quality predictions possible. Initial bacteria levels on the chicken drumsticks were uniform and not judged as important limiting factors in the application of TTIs to poultry products. Because the poultry spoilage process was reasonably characterized on the basis of Arrhenius kinetics, there is further need to conduct validation studies to determine the ability of TTIs to provide a continuous quality monitoring system.}, number={2}, journal={JOURNAL OF FOOD PROTECTION}, author={Moore, CM and Sheldon, BW}, year={2003}, month={Feb}, pages={280–286} }
 @article{xu_sheldon_larick_carawan_2002, title={Recovery and utilization of useful by-products from egg processing wastewater by electrocoagulation}, volume={81}, ISSN={["0032-5791"]}, DOI={10.1093/ps/81.6.785}, abstractNote={The efficacy of a laboratory electrocoagulation (EC) system for treating egg processing plant waste-water (WW) is reported. For simulated and industrial egg processing WW, chemical oxygen demand, turbidity, and total suspended solids (TSS) were reduced 92 to 97%, 97%, and 99%, respectively, after treatment with EC. The final TSS concentration and turbidity values were 30 mg/L and 5 formazin turbidity units (FTU), respectively, similar to that of potable water standards. The recovered by-product solids had a similar pattern of essential amino acids compared to that of liquid whole egg and were comparable to the Food Agriculture Organization's essential amino acid profile for an ideal protein. The relative protein digestibilities of the recovered solids and a commercial corn meal averaged 130 and 56%, respectively, compared to liquid whole egg (set at 100%). An economic analysis of EC indicated that this treatment is economically feasible in that a savings of approximately $425,000 per year is possible in addition to recovering the capital equipment costs after about 14 mo of operation. These findings demonstrate that EC can be successfully applied to treat egg processing plant WW, yielding a high quality water suitable for recycling and valuable by-products having a highly digestible protein and fat value.}, number={6}, journal={POULTRY SCIENCE}, author={Xu, LJ and Sheldon, BW and Larick, DK and Carawan, RE}, year={2002}, month={Jun}, pages={785–792} }
 @article{poland_sheldon_2001, title={Altering the thermal resistance of foodborne bacterial pathogens with an eggshell membrane waste by-product}, volume={64}, ISSN={["0362-028X"]}, DOI={10.4315/0362-028X-64.4.486}, abstractNote={Eggshells from egg-breaking operations are a significant waste disposal problem. Thus, the development of value-added by-products from this waste would be welcomed by the industry. The ability of extracted eggshell membranes containing, several bacteriolytic enzymes (i.e., lysozyme and beta-N-acetylglucosaminidase) or other membrane components to alter the thermal resistance of gram-positive and gram-negative bacterial pathogens was evaluated. Mid-log phase cells of Salmonella Enteritidis (SE), Salmonella Typhimurium (ST), Escherichia coli O157:H7 (EC), Listeria monocytogenes Scott A (LM), and Staphylococcus aureus (SA) were suspended in 100 ml of 0.1% peptone water (pH 6.9, 10(7-8) CFU/ml) containing either 0 (control) or 10 g of an eggshell membrane extract and incubated at 37 degrees C for 45 min. Following exposure, membrane-free samples (1.5 ml) were heated in a 56 degrees C (LM, SA), 54 degrees C (SE, ST), or 52 degrees C (EC) water bath from 0 to 14 min in sealed glass reaction vials (12 by 32 mm), and the survivors were recovered on brain heart infusion agar. Population reductions ranging from 27.6% (SA) to 99.8% (LM) (ST, 43.8%; SE, 47.5%; EC, 71.8%) were observed for cells treated for 45 min with extracted membrane, as compared to controls. D-value reductions ranging from 0 (LM) to 87.2% (SE) (SA, 36.7%; EC, 83.3%; ST, 86.3%) were observed when membrane-treated cells were subsequently heat inactivated. The effects of exposure pH, time, temperature, and organic load on membrane activity were also evaluated with Salmonella Typhimurium. Exposure pH (5.0 versus 6.9), time (15 versus 45 min), and temperature (4 degrees C versus 37 degrees C) did not significantly reduce the impact of eggshell membranes on D-values. However, the presence of organic matter (0.1% peptone water versus skim milk) significantly reduced the thermal resistance-reducing capacity of the membranes. These preliminary findings provide information on the potential use of extracted eggshell membranes to alter bacterial heat resistance.}, number={4}, journal={JOURNAL OF FOOD PROTECTION}, author={Poland, AL and Sheldon, BW}, year={2001}, month={Apr}, pages={486–492} }
 @article{xu_sheldon_carawan_larick_chao_2001, title={Recovery and characterization of by-products from egg processing plant wastewater using coagulants}, volume={80}, DOI={10.1093/ps/80.1.57}, abstractNote={The effectiveness of precipitation or coagulation technology to treat commercial egg processing plant wastewater, using such coagulants as lignosulfonate, bentonite, carboxymethylcellulose, and ferric chloride, was evaluated. For simulated and industrial waste-water, chemical oxygen demand, turbidity, and total solids were reduced over 90, 97, and 95%, respectively, for all coagulants tested. Protein and fat recoveries were over 95% for all coagulants. The optimal coagulant concentration for maximum by-product recovery depended on initial wastewater concentrations of protein, total solids, and fat. The dried by-products contained high concentrations of protein (30 to 50%) and fat (30 to 40%) and had similar essential amino acid profiles as standard proteins from the United Nations Food and Agricultural Organization (FAO). The relative protein digestibilities of each recovered solid (carboxymethycellulose, lignosulfonate, bentonite, and ferric chloride) and corn meal relative to a liquid whole egg standard were approximately 80, 90, 60, 30, and 56%, respectively. These compositional and in vitro digestibility studies suggest that the recovered by-products could be useful as livestock feed ingredients or for other applications.}, number={1}, journal={Poultry Science}, author={Xu, L. J. and Sheldon, B. W. and Carawan, R. E. and Larick, D. K. and Chao, A. C.}, year={2001}, pages={57–65} }
 @article{natrajan_sheldon_2000, title={Efficacy of nisin-coated polymer films to inactivate Salmonella Typhimurium on fresh broiler skin}, volume={63}, ISSN={["1944-9097"]}, DOI={10.4315/0362-028X-63.9.1189}, abstractNote={Nisin is an antimicrobial peptide produced by the food-grade microorganism Lactococcus lactis subsp. lactis. This peptide inhibits many gram-positive bacteria, and when combined with chelating agents it inhibits gram-negative bacteria such as Salmonella sp. The efficacy of packaging films treated with nisin-containing formulations to reduce Salmonella contamination of fresh broiler drumstick skin and increase the refrigerated shelf life was investigated. Three films (5.1 cm2) of varying hydrophobicities (polyvinyl chloride [PVC], linear low density polyethylene, nylon) were coated with one of three liquid formulations (pH 3.5 to 3.8) composed of 100 microg/ml nisin and varying concentrations of citric acid, EDTA, and Tween 80. The treated films were applied either wet or dry to 5.1-cm2 broiler drumstick skin samples inoculated with a nalidixic acid-resistant (NAr) strain of Salmonella Typhimurium. After incubation at 4 degrees C for 24 h the populations of surviving Salmonella TyphimuriumNAr organisms were recovered from the skin and film samples using a rinse procedure and enumerated on brain heart infusion agar containing 800 ppm NA. Log reductions (untreated versus treated skin) in Salmonella TyphimuriumNAr populations ranged from 0.4 to 2.1. Treatment formulation compositions and wet versus dry treatment application also influenced the extent of kill. The shelf life of refrigerated broiler drumsticks was extended by 0.6 to 2.2 days following a 3-min immersion in a nisin-containing treatment solution and subsequent storage in a foam tray pack containing a nisin-treated PVC overwrap and a nisin-treated absorbent tray pad. These findings demonstrated that Salmonella Typhimurium and spoilage microorganism populations on the surface of fresh broiler skin and drumsticks can be significantly reduced using immersion treatments, absorbent tray pads, and packaging films treated with nisin-containing formulations.}, number={9}, journal={JOURNAL OF FOOD PROTECTION}, author={Natrajan, N and Sheldon, BW}, year={2000}, month={Sep}, pages={1189–1196} }
 @article{natrajan_sheldon_2000, title={Inhibition of Salmonella on poultry skin using protein- and polysaccharide-based films containing a nisin formulation}, volume={63}, ISSN={["1944-9097"]}, DOI={10.4315/0362-028X-63.9.1268}, abstractNote={The objective of this study was to examine the use of protein- arid polysaccharide-based films containing bacteriocin formulations for inhibiting salmonellae on fresh broiler skin. The lethality of the films containing a nisin-based formulation was determined against Salmonella Typhimurium-contaminated broiler drumstick skin samples coated with the film. In the first study, varying concentrations of nisin (0, 100, 300, and 500 microg/ml) plus 3% citric acid, 5.0 mM EDTA, and 0.5% Tween 80 were incorporated into 0.5% calcium alginate films at a 20% level (wt/wt) and then applied to Salmonella TyphimuriumNAr-contaminated skin samples (log10 5.0) at a 1:2 weight ratio (film:skin). Salmonella TyphimuriumNAr skin population reductions ranged from 1.98 to 3.01 log cycles after a 72-h exposure at 4 degrees C. In comparison to the 0- and 100-microg/ml nisin concentrations, significantly greater population reductions were achieved at nisin concentrations of 300 and 500 microg/ml. In related studies, the 500-degreesg/ml nisin formulation was incorporated into 0.75 and 1.25% agar gels and applied to contaminated broiler drumstick skin samples (log10 7.0). Salmonella TyphimuriumNAr skin population reductions following a 96-h exposure at 4 degrees C were 1.8-(1.25% agar gel) and 4.6-log cycles (0.75% agar gel). These results demonstrated that the inclusion of nisin-based treatments into either calcium alginate or agar gels that were subsequently applied to contaminated broiler drumstick skin yielded significant Salmonella TyphimuriumNAr population reductions ranging between 1.8 to 4.6 log cycles after 72 to 96 h of exposure at 4 degrees C. The level of kill was affected by film type and gel concentration (i.e., gel network formation), exposure time, and nisin concentration.}, number={9}, journal={JOURNAL OF FOOD PROTECTION}, author={Natrajan, N and Sheldon, BW}, year={2000}, month={Sep}, pages={1268–1272} }
 @article{shefet_sheldon_farkas_swartzel_1999, title={Development of a quantitative video-based visualization method to characterize the flow behavior of food particulates in a model continuous aseptic sterilizer}, volume={22}, ISSN={["0145-8876"]}, DOI={10.1111/j.1745-4530.1999.tb00477.x}, abstractNote={ABSTRACT}, number={2}, journal={JOURNAL OF FOOD PROCESS ENGINEERING}, author={Shefet, SM and Sheldon, BW and Farkas, BE and Swartzel, KR}, year={1999}, month={Jul}, pages={141–160} }
 @article{wandling_sheldon_foegeding_1999, title={Nisin in milk sensitizes Bacillus spores to heat and prevents recovery of survivors}, volume={62}, ISSN={["1944-9097"]}, DOI={10.4315/0362-028X-62.5.492}, abstractNote={Decimal reduction times (D values) were determined for Bacillus cereus T spores and B. stearothermophilus ATCC 12980 spores in skim milk supplemented with various concentrations (0, 2,000, and 4,000 IU/ml) of the bacteriocin nisin by using an immersed, sealed capillary tube procedure. For both organisms, the addition of nisin lowered the apparent D values. For B. cereus, the addition of 2,000 IU of nisin per ml to skim milk before heating significantly (P< or =0.05) lowered the apparent D value compared to the control treatment. The D values at 97 degrees C were 7.0, 4.8, and 4.7 min for the control and 2,000- and 4,000-IU/ml nisin treatments, respectively. At 103 degrees C, the D values were 1.5, 0.85, and 0.88 min for the control and 2,000-and 4,000-IU/ml nisin treatments. When calculated across both nisin treatments, the mean reductions in apparent D values at 97, 100, and 103 degrees C due to addition of nisin in comparison to the controls were 32, 20, and 42%, respectively. The zD values for B. cereus ranged from 8.0 to 8.9 degrees C. With B. stearothermophilus, the apparent D values at 130 degrees C were reduced by 13 and 21% respectively, because of the presence of 2,000 or 4,000 IU of nisin per ml. The D values were 16.0, 13.8, and 12.5 s for the control and 2,000- and 4,000-IU/ml nisin treatments, respectively. There was a significant (P< or =0.05) decrease in the apparent D value between the control and 4,000-IU/ml treatment. Overall, log populations of survivors for B. stearothermophilus compared to the control were lower at any given sampling time due to the presence of nisin. The results of these studies suggest that spore control is likely due to enhanced sensitivity of spores to heat and the presence of residual nisin in the recovery medium that could prevent outgrowth of survivors.}, number={5}, journal={JOURNAL OF FOOD PROTECTION}, author={Wandling, LR and Sheldon, BW and Foegeding, PM}, year={1999}, month={May}, pages={492–498} }
 @article{beard_sheldon_foegeding_1999, title={Thermal resistance of bacterial spores in milk-based beverages supplemented with nisin}, volume={62}, ISSN={["1944-9097"]}, DOI={10.4315/0362-028X-62.5.484}, abstractNote={The effect of nisin, added in the form of Nisaplin, on the thermal resistance of bacterial spores and the effects of medium composition, exposure time, and pH on nisin enhancement of heat sensitivity were evaluated. Nisin apparently required specific nutrients to sensitize spores to heat. For example, D130 degrees C values of approximately 10 s were observed in sodium phosphate buffer with and without 6% sucrose with no significant (P> or =0.05) differences detected as a result of increased nisin concentration. In a nutrient-rich chocolate milk model system (CMMS), increasing either the time of exposure to nisin (5, 15, or 24 h) before heating or nisin concentration (0, 2,000, or 4,000 IU/ml) increased the sensitivity of Bacillus stearothermophilus spores to heat. In the CMMS with 10 to 12% fat cocoa powder, increasing nisin concentration (at 5 h of exposure) significantly (P< or =0.05) reduced D130 degrees C values; D130 degrees C values were 21.7, 17.2, and 17.8 s, respectively, for the 0-, 2,000-, and 4,000-IU/ ml nisin treatments. Fifteen and 24 h of exposure further reduced D130 degrees C values in the nisin-containing treatments compared to the control (0 IU of nisin per ml). A lower-fat CMMS (0 to 1% fat cocoa powder) had lower D130 degrees C values (19.3, 15.8, and 14.7 s for the 0-, 2,000-, and 4,000-IU/ml nisin treatments, respectively). Nisin activity was enhanced by lowering pH in the CMMS (10 to 12% fat cocoa powder), with reductions in D130 degrees C values across all pH values (ranging from 18.0% at pH 6.4 to 41.9% at pH 5.0). zD values were 9.6, 9.0, and 8.4 degrees C for the 0-, 2,000-, and 4,000-IU/ml nisin treatments, respectively. Spores of B. licheniformis yielded results similar to those obtained with B. stearothermophilus. For example, decreasing CMMS (10 to 12% fat cocoa powder) pH values from 6.4 to 5.0 produced D100 degrees C values of 3.3, 2.8, and 2.8 min (pH 6.4) and 1.0, 0.8, and 0.8 min (pH 5.0) for the 0-, 2,000-, and 4,000-IU/ml nisin treatments. This study clearly verified that the addition of Nisaplin to dairy-based beverages, such as a chocolate milk drink, or other foods intended to be heated reduces the thermal resistance of selected bacterial spores. Increased spore sensitivity to heat may provide food processors with an opportunity to reduce their thermal processes and expenses while maintaining product quality, functionality, and shelf stability.}, number={5}, journal={JOURNAL OF FOOD PROTECTION}, author={Beard, BM and Sheldon, BW and Foegeding, PM}, year={1999}, month={May}, pages={484–491} }
 @article{sheldon_curtis_dawson_ferket_1997, title={Effect of dietary vitamin E on the oxidative stability, flavor, color, and volatile profiles of refrigerated and frozen turkey breast meat}, volume={76}, ISSN={["0032-5791"]}, DOI={10.1093/ps/76.4.634}, abstractNote={In this study, the effect of varying dietary vitamin E levels on the oxidative stability, flavor, color, and volatile profiles of refrigerated and frozen turkey breast meat was examined. Nicholas turkey toms were reared on diets containing vitamin E levels as dl-alpha-tocopheryl acetate equivalent to the NRC recommendations (12 and 10 IU/kg from 0 to 8 and 9 to 18 wk, respectively) and 5x, 10x, and 25x the NRC diet. Two other diets were evaluated and included feeding the NRC diet until 15 and 16 wk followed by a diet containing 20x the NRC vitamin E level. All turkeys were processed in a commercial turkey processing plant and breast meat scored for color. Breast meat was excised from four carcasses per treatment and evaluated after refrigeration (1 and 7 d) or frozen storage (30, 90, 150 d) for oxidative stability and sensory quality by TBA analysis, descriptive flavor profiling, and headspace gas chromatography. The TBA values were inversely related to the dietary vitamin E levels. Refrigerated samples had TBA values 78 to 88% lower for the 10x and 25x vitamin E treatments, respectively, than for the NRC control treatment. No differences in TBA values (refrigerated samples) were detected for the 10x, 25x, and 20x (3 wk feeding duration) or across all treatments for samples frozen for 5 mo. The 10x and 25x NRC diets produced the most typical and acceptable turkey meat flavors with the fewest oxidized off-flavor notes for both fresh and frozen samples as opposed to the more oxidized flavor notes detected in the control samples. Mean color scores increased, indicative of less pale meat, as the level and duration of feeding dietary vitamin E increased. These findings showed that varying dietary vitamin E levels significantly influenced the oxidative stability and functionality of turkey breast meat.}, number={4}, journal={POULTRY SCIENCE}, author={Sheldon, BW and Curtis, PA and Dawson, PL and Ferket, PR}, year={1997}, month={Apr}, pages={634–641} }
 @article{schuman_sheldon_vandepopuliere_ball_1997, title={Immersion heat treatments for inactivation of Salmonella enteritidis with intact eggs}, volume={83}, ISSN={["1364-5072"]}, DOI={10.1046/j.1365-2672.1997.00253.x}, abstractNote={The effects of water‐bath immersion heat treatments on the inactivation of Salmonellaenteritidis within intact shell eggs were evaluated. Six pooled strains of Salm. enteritidis (ca 3×108 cfu, inoculated near the centre of the yolk) were completelyinactivated within 50–57·5 min at a bath temperature of 58°C and within 65–75min at 57°C (an 8·4 to 8·5‐D process per egg). Following the initial 24 to35‐min come‐up period, semilogarithmic survivor curves obtained at 58 and 57°C yieldedapparent decimal reduction times (D‐values) of 4·5 and 6·0 min, respectively.Haugh unit values increased during heating, while yolk index and albumen pH values wereunaffected. Albumen clarity and functionality were affected by the thermal treatments; therefore,extended whip times would be required for meringue preparation using immersion‐heated eggwhites. Immersion‐heated shell eggs could provide Salmonella‐free ingredients for thepreparation of a variety of minimally‐cooked foods of interest to consumers and foodserviceoperators.}, number={4}, journal={JOURNAL OF APPLIED MICROBIOLOGY}, author={Schuman, JD and Sheldon, BW and Vandepopuliere, JM and Ball, HR}, year={1997}, month={Oct}, pages={438–444} }
 @article{schuman_sheldon_foegeding_1997, title={Thermal resistance of Aeromonas hydrophila in liquid whole egg}, volume={60}, ISSN={["0362-028X"]}, DOI={10.4315/0362-028X-60.3.231}, abstractNote={Aeromonas hydrophila (AH) is a psychrotrophic spoilage bacterium and potential pathogen which has been isolated from a variety of refrigerated foods of animal origin, including raw milk, red meat, poultry, and commercially broken raw liquid whole egg (LWE). Decimal reduction times (D values) of 4 strains of AH (1 egg isolate, 2 egg processing plant isolates, 1 ATCC type strain) were determined in LWE using an immersed sealed capillary tube (ISCT) procedure. Initial populations (7.0 to 8.3 log CFU/tube in 0.05 ml LWE) were heated at 48, 51, 54, 57, and 60°C, and survivors were plated onto starch ampicillin agar (48 h at 28°C). D values ranged from 3.62 to 9.43 min (at 48°C) to 0.026 to 0.040 min (at 60°C). Both processing plant isolates were more heat resistant than the ATCC strain. Decimal reduction time curves (r2 ≤ 0.98) yielded ZD values of 5.02 to 5.59°C, similar to those for other non-spore-forming bacteria. D values of the most heat resistant AH strain were also determined in LWE at 48, 51, and 54°C using a conventional capped test tube procedure (10 ml/tube). Cells heated in test tubes yielded nonlinear (tailing) survivor curves and larger (P ≤ 0.05) apparent D values at each temperature than those obtained using the ISCT method. This study provides the first thermal resistance data for AH in LWE and the first evidence that straight-line semilogarithmic thermal inactivation kinetics may be demonstrated for Aeromonas using the ISCT procedure.}, number={3}, journal={JOURNAL OF FOOD PROTECTION}, author={Schuman, JD and Sheldon, BW and Foegeding, PM}, year={1997}, month={Mar}, pages={231–236} }
 @article{schuman_sheldon_1997, title={Thermal resistance of Salmonella spp. and Listeria monocytogenes in liquid egg yolk and egg white}, volume={60}, ISSN={["0362-028X"]}, DOI={10.4315/0362-028X-60.6.634}, abstractNote={Decimal reduction times (D values) were determined for Salmonella spp. and Listeria monocytogenes (five pooled strains per pathogen) in raw liquid egg yolk (pH 6.3) and liquid egg white (pH 8.2 versus 9.1) by using a low-volume (0.05 ml per sample) immersed sealed-glass capillary-tube procedure. For Salmonella , D values ranged from 0.087 min (at 62.2°C) to 0.28 min (at 60°C) in yolk. and from 1.00 min (at 58.3°C) to 7.99 min (at 55.1° C) in egg white (pH 8.2). For Listeria , D values ranged from 0.58 min (at 62.2°C) to 1.34 min (at 60°C) in yolk, and from 2.41 min (at 58.3°C) to 7.59 min (at 55. 1°C) in egg white (pH 9.1). Mean ZD values for Salmonella ranged from 3.54 to 4.33°C; for Listeria , ZD values ranged from 6.06 to 9.43°C. In egg white, the heat sensitivity of both pathogens was enhanced at pH 9.1, although this trend was more evident for Salmonella spp. than for L. monocytogenes over the temperature range tested. The results indicate that USDA-prescribed minimal pasteurization requirements for liquid egg yolk (equivalent to 3.9- to 22.1-D processes, on the basis of the present study) would be far more lethal to the Salmonella and L. monocytogenes strains tested than would the corresponding thermal processes for liquid egg white (equivalent to 0.7- to 2.2-D processes).}, number={6}, journal={JOURNAL OF FOOD PROTECTION}, author={Schuman, JD and Sheldon, BW}, year={1997}, month={Jun}, pages={634–638} }
 @article{sheldon_schuman_1996, title={Thermal and biological treatments to control psychrotrophic pathogens}, volume={75}, ISSN={["0032-5791"]}, DOI={10.3382/ps.0751126}, abstractNote={Over the past decade, advances in egg processing technologies have permitted commercial production of ultrapasteurized liquid whole egg (LWE) products with a shelf-life of greater than 10 wk at 4 C. The inactivation and control of psychrotrophic pathogens such as Listeria monocytogenes and Aeromonas hydrophila in extended shelf-life LWE and conventionally pasteurized egg products is an ongoing food safety concern. This manuscript reports on the common features of these two psychrotrophic pathogens, their incidence in egg products, and their survival, growth potential, and heat resistance in liquid egg. Furthermore, this manuscript reports in detail on the results of two specific studies conducted in our laboratory whose objectives were: 1) to determine the heat resistance (D-values) of A. hydrophila in LWE using a low-volume immersed sealed glass capillary tube (ISCT) procedure; 2) to assess the impact of methodology (i.e., ISCT procedure vs a conventional capped test tube procedure) on the apparent thermal resistance of A. hydrophila; and 3) to report on the use of the bacteriocin nisin to restrict the survival of L. monocytogenes in ultrapasteurized LWE stored at refrigeration temperatures.}, number={9}, journal={POULTRY SCIENCE}, author={Sheldon, BW and Schuman, JD}, year={1996}, month={Sep}, pages={1126–1132} }
 @article{dawson_sheldon_miles_1991, title={EFFECT OF ASEPTIC PROCESSING ON THE TEXTURE OF CHICKEN MEAT}, volume={70}, ISSN={["0032-5791"]}, DOI={10.3382/ps.0702359}, abstractNote={Abstract Breast meat containing collagen at high concentrations (spent hen, 20 to 24 mo of age) and low concentrations (broiler, 6 to 7 wk of age) was evaluated for texture following high-temperature, short-time processing at 121, 130, and 145 C in a laboratory scale processing system. Breast meat was evaluated for proximate composition, collagen content, Kramer shear texture, Warner-Bratzler shear texture, and texture profile panel characteristics. Process parameters were adjusted across all processing temperatures to obtain a theoretical 12 log10 population reduction of Clostridium botulinum spores. Aseptic processing resulted in significant moisture losses and toughening of the breast meat, which may be attributed to protein denaturation and myofibrillar shortening. Furthermore, the higher the processing temperature, the tougher and drier the meat and the lower the processing yields. Although the aseptic high-temperature, short-time process extracted and solubilized collagen, the process resulted in a tougher final meat texture. The profile panel identified seven texture characteristics that were significantly affected by aseptic processing. The total energy parameter of the Kramer shear test was significantly correlated to all seven texture characteristics identified by the panel. The results of the present study indicated that both high-temperature, short-time processing conditions and meat type significantly affected the proximate composition and textural characteristics of the finished product.}, number={11}, journal={POULTRY SCIENCE}, author={DAWSON, PL and SHELDON, BW and MILES, JJ}, year={1991}, month={Nov}, pages={2359–2367} }
 @article{sheldon_brake_1991, title={Hydrogen peroxide as an alternative hatching egg disinfectant}, volume={70}, ISSN={["0032-5791"]}, DOI={10.3382/ps.0701092}, abstractNote={The present study examined the effectiveness of H2O2 at different concentrations to disinfect broiler hatching eggshell surfaces and to maintain hatching potential. Under pure culture conditions, .50% H2O2 yielded over a 6 log kill in 30 s of three potential eggshell bacterial contaminants. Under higher H2O2 demands, such as occurs on eggshell surfaces, H2O2 concentrations of 5% (vol/vol) were required to disinfect the shell surfaces (approximately 5 log reduction). Hatchability of fertile eggs from a 44-wk-old flock was significantly increased by 2% following spraying 5% H2O2 in comparison to untreated controls. Level of contaminated eggs and "early-dead" embryos were significantly reduced in the H2O2-treated eggs. In comparison with formaldehyde fumigation, no significant difference in hatchability due to H2O2 treatment was detected in eggs from a 30- or 56-wk-old flock. Eggshell permeability, as measured by egg moisture loss in an incubator, was not significantly affected by H2O2 (5%) or formaldehyde fumigation when compared with untreated or water-sprayed control eggs. These results demonstrated that H2O2 compared favorably to formaldehyde as a hatching egg disinfectant without adversely affecting hatching potential. Under some conditions, H2O2 actually improved the hatching potential of fertile broiler eggs compared with hatchability of untreated eggs.}, number={5}, journal={Poultry Science}, author={Sheldon, B.W. and Brake, J.}, year={1991}, pages={1092–1098} }
 @misc{sheldon_brake_1990, title={Method for sanitizing and improving the hatchability of hatchery eggs}, volume={4932359}, publisher={Washington, DC: U.S. Patent and Trademark Office}, author={Sheldon, B. W. and Brake, J. T.}, year={1990} }
 @article{sheldon_tarver_1987, title={COMPARISON OF CARCASS AND COOKING YIELDS ACROSS 5 WEIGHT CLASSES FOR 7 COMMERCIALLY AVAILABLE READY-TO-COOK DUCKLING BRANDS}, volume={66}, ISSN={["0032-5791"]}, DOI={10.3382/ps.0660995}, abstractNote={Abstract Raw and cooked yields of ready-to-cook ducklings representing seven commercially available brands across five weight classes were determined. Derived model equations for predicting breast weight from eviscerated weight were also tested. Significant brand differences within weight classes were found for the majority of tissues evaluated. Skin and fat yields between brands and across weight classes ranged from 28.5 to 40.6% of eviscerated weight. Significant brand differences across weights were also detected for breast, legs, wings, and carcass frame weights and yields. Overall, considerable brand variation was detected in the ratio of edible to inedible yields, ranging from .952 to .711. Although no significant brand differences for whole carcass cooked yields were detected, breast fillet cooked yields were significantly influenced by brand. Breast weights were accurately predicted from eviscerated weights using derived linear regression equations. The predicted mean absolute deviation ranged from 18.8 to 32.1 g away from actual breast weight. These findings illustrate that similar derived equations could be used by the processor to determine if carcasses are better suited for whole carcass, cut-up, or further-processing market.}, number={6}, journal={POULTRY SCIENCE}, author={SHELDON, BW and TARVER, FR}, year={1987}, month={Jun}, pages={995–1000} }
 @article{sheldon_tarver_kimsey_1982, title={YIELDS FROM COMMERCIALLY AVAILABLE READY-TO-COOK DUCKLINGS}, volume={61}, ISSN={["0032-5791"]}, DOI={10.3382/ps.0610601}, abstractNote={Abstract Seven commercially available brands of two ducklings each were dissected for edible and inedible yields. Carcass weights, part weights, and percent yields varied even though ducklings were of similar age. These differences are attributed in part to variations in diets, growth rates, and muscle conformation of duckling strains. A highly significant positive correlation was found between die length of the keel bone and breast weight.}, number={3}, journal={POULTRY SCIENCE}, author={SHELDON, BW and TARVER, FR and KIMSEY, HR}, year={1982}, pages={601–603} }