@article{smith_reimers_barnes_lee_siletzky_kathariou_2004, title={Campylobacter colonization of sibling turkey flocks reared under different management conditions}, volume={67}, ISSN={["1944-9097"]}, DOI={10.4315/0362-028X-67.7.1463}, abstractNote={Uncertainty exists concerning the key factors contributing to Campylobacter colonization of poultry, especially the possible role of vertical transmission from breeder hens to young birds. A longitudinal study of Campylobacter colonization was performed in two sibling pairs of turkey flocks (four flocks total). Each pair of sibling flocks shared breeder hen populations and was obtained from the same hatchery. One flock of each pair was grown on a commercial farm, and the other was grown in an instructional demonstration unit (Teaching Animal Unit [TAU]). Flocks were located within a 60-mi (96.8-km) radius. The time of placement, feed formulations, stocking density, and general husbandry were the same for both flocks, and each flock was processed at a commercial processing plant following standard feed withdrawal and transport protocols. Both flocks grown on the commercial farms became colonized with Campylobacter between weeks 2 and 3 and remained colonized until processing. Between 80 and 90% of isolates were Campylobacter coli, and the remainder were Campylobacter jejuni. In contrast, neither C. coli nor C. jejuni were isolated from either of the TAU flocks at any time during the production cycle. None of the fla types of Campylobacter from the breeders that provided poults to one of the commercial flocks matched those from the progeny. These results failed to provide evidence for vertical transmission and indicate that this type of transmission either did not occur or was not sufficient to render the TAU turkey flocks Campylobacter positive. Management practices such as proper litter maintenance, controlled traffic between the TAU farm and other turkey flocks, and other less well-defined aspects of turkey production were likely responsible for the absence of Campylobacter in the TAU flocks before harvest.}, number={7}, journal={JOURNAL OF FOOD PROTECTION}, author={Smith, K and Reimers, N and Barnes, HJ and Lee, BC and Siletzky, R and Kathariou, S}, year={2004}, month={Jul}, pages={1463–1468} }
 @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} }