The effect of incubation temperature on recovery of mesophilic bacteria from broiler chicken carcasses subjected to temperature abuse.

The optimum temperature to recover mesophilic organisms from temperature-abused broiler chicken carcasses was determined. Twenty broiler carcasses were collected from a commercial processing plant in each of three trials. Ten carcasses were sampled immediately (Day 0 control); 8 carcasses were sampled after holding at 3 C for 3 d, temperature abusing at 25 C for 12 h, and holding them at 3 C for an additional 3 d (temperature abused); and the remaining 2 carcasses were sampled after holding at 3 C for 7 d (Day 7 control). Whole carcass rinses were analyzed using total aerobic plate counts (TPC) and impedimetric detection times (DT) at incubation temperatures of 41, 42, 43, and 44 C. Total plate counts decreased (P < .05) and DT increased (P < .05), at all incubation temperatures tested, for carcasses held under refrigeration (Day 7 control). This demonstrates that mesophilic bacteria, rather than psychrotrophic bacteria, are being enumerated, because psychrotrophs increase on chicken skin upon cold storage. Total plate count was greater (P < .05) and DT was significantly lower for temperature-abused vs Day 7 control birds (5.7 vs 3.6 log10 cfu/mL and 3.7 vs 6.5 h), respectively. These results indicate that temperature-abused carcasses can be microbiologically distinguished from nonabused controls at all incubation temperatures tested. Recovery of mesophiles was optimal at 41 and 42 C for TPC and 41, 42, and 43 C for DT. Because there were no differences between DT at 41, 42, and 43 C, and because 42 C has been successfully used in the past, either 42 C or 43 C can be used when determining DT.