EFFECT OF FREEZING ON THE RECOVERY OF MESOPHILIC BACTERIA FROM TEMPERATURE-ABUSED BROILER CHICKEN CARCASSES

The effects of freezing on the recovery of mesophilic bacteria from br oiler chicken carcasses were determined. Fifty fresh broiler carcasses were used in each of three independent trials. Ten carcasses were sam pled at time of collection (Treatment 1: Day 0 control). The other 40 carcasses were sampled at Day 7 following one of four additional treat ments with 10 carcasses each: held at 3 C (Treatment 2: 7-d control), frozen and then held at 3 C (Treatment 3: frozen control), temperature abused at 25 C for 12 h and held at 3 C (Treatment 4: temperature abu sed), and temperature abused at 25 C for 12 h, frozen, and held at 3 C (Treatment 5: temperature abused and frozen). Carcasses were sampled by rinsing, and total plate counts (TPC) expressed as log10 colony-for ming units per milliliter and impedance detection times (DT) in hours were determined using incubation temperatures of 42 and 43 C, respecti vely. Results for TPC for Treatments 1 to 5 were 3.89, 3.52, 2.86, 6.5 3, and 5.57 log10 cfu/mL, respectively. Results for DT for Treatments 1 to 5 were 5.41, 6.50, 7.10, 2.55, and 3.42 log10 cfu/mL, respectivel y. Freezing reduced the ability to detect temperature abuse because of a significant reduction in the number of mesophiles recovered using e ither microbiological technique. Freezing appears to decrease, but may not completely eliminate, the ability of selective incubation to dete ct temperature abuse.