Influence of flooring type during transport and holding on bacteria recovery from broiler carcass rinses before and after defeathering

Four trials were conducted to determine whether conventional solid or elevated wire mesh flooring, during transport and holding of broilers prior to slaughter, influenced the number of bacteria recovered from feathered and defeathered carcasses. After 4 h off feed, 7-wk-old broilers were placed at commercial density into a modified commercial transport dump-coop on either fiberglass sheeting or 2.54 x 2.54 cm wire mesh flooring that allowed feces to fall through. Broilers were transported for 1 h and then held for 13 h under a covered shed before processing. Broilers were killed by electrocution, and the vents were plugged to prevent escape of feces. External carcass rinses were obtained twice (from the same carcass) from eight broilers per flooring treatment per trial, before scalding and defeathering and again after defeathering and removal of the head and feet. Greater numbers of total aerobes, coliforms, and Escherichia coli were recovered from feathered carcasses than from defeathered carcasses. Campylobacter count was also less for defeathered than feathered carcasses from the solid flooring treatment but did not significantly decrease following defeathering of carcasses from the wire flooring. The incidence of Campylobacter-positive carcasses was reduced following defeathering for both flooring treatments, but the percentage of Salmonellae-positive carcasses remained constant. Coliform (log(10) 6.20 vs. 5.63 cfu/mL of rinse) and E. coli (log(10) 5.93 vs. 5.36) counts in the feathered rinses were significantly higher for the solid flooring compared with wire flooring, respectively. After defeathering, the number of coliforms (log(10) 3.12) and E. coli (log(10) 2.91) recovered did not differ between flooring treatments. Aerobic plate count (log(10) 7.06 and 4.02), Campylobacter count (log(10) 2.49 and 1.80), and the incidence of Campylobacter-positive (44 and 11%) and Salmonellae-positive (52 and 50%) carcasses for feathered and defeathered rinses, respectively, did not differ between flooring treatments. These results indicate that although broilers transported and held on solid flooring had noticeably dirtier breast feathers and higher coliform and EI coli counts prior to scalding and defeathering, bacteria recovery from external carcass rinses did not differ between the solid and wire flooring treatments after defeathering.