Reference | Price2007 (20016)

producers. We included products from five different poultry producers in the present study: A) Bell & Evans (Fredericksburg, PA); B) Murray's (South Fallsburg, NY); C) Eberly (Stevens, PA); D) Perdue (Salisbury, MD); and E) Tyson (Springdale, AR). Producers A-C claim that their chickens are raised without any antibiotics, including fluoroquinolones. We refer to these producers and their products as antibiotic-free. Producers D and E do not claim general prohibitions on antibiotics; we refer to these producers and their products as conventional. A critical caveat to this desig- nation is that each of the conventional produc- ers announced separately in February 2002 that they had adopted company policies pro- hibiting the use of fluoroquinolones. In the same announcement, producer D claimed that no fluoroquinolones had been used in the year before the announcement. Finally, all produc- ers except producer C claimed to exclusively slaughter their own flocks in their processing plants. Representatives from producer C acknowledged that custom flocks, including those treated with antibiotics, were occasion- ally processed in their facilities during the study period.

We purchased fresh chicken products from grocery stores in the Baltimore, Maryland, area on a weekly basis from 19 January 2004 to 7 June 2004 and from 20 February 2006 to 5 June 2006. Two to three packages from each of the five producers were purchased each time (except when availability was limited). Thighs and legs (bone-in and skin-on) were the default cuts for the study. However, these cuts were not consistently available for all producers; in those cases, we tested alternative cuts, includ- ing breasts, quarters, and whole chickens. Packages were refrigerated at 40C until they were sampled (within 48 hr of purchase). A single piece of chicken was sampled from each package as follows. First, each package was wiped with 70% ethanol and cut open with a new disposable razor blade; the plastic cover was then removed and photocopied for our records. We used sterile forceps to transfer the entire piece of chicken to a stomacher bag containing 200 mL sterile Bolton broth supplemented with laked horse blood (Quad Five, Ryegate, MT); samples were shaken by hand for 2 min, the chicken was removed using forceps, and the bag was sealed 1-2 cm above the top of the broth. Enrichments were incubated at 42C for 22-26 hr (Hunt 2000; Price et al. 2005).

AST Method: None

Reference explicitly reports AST breakpoints: True

Reference reports using a MIC table: False