Microbial properties of color-modified turkey

Studies were performed to determine the effect of color modification procedures on the microbial characteristics of turkey thigh meat. Turkey thighs were flaked and then color modified successively with three sodium phosphate buffers (pH 5.8, 7.4, and 8.0). At selected time intervals, flaked unwashed turkey (FUT; control) and color-modified turkey (CMT) stored at 3°C were analyzed for aerobic, psychrotrophic, and coliform bacterial counts. Aerobic and psychrotrophic numbers also were estimated in raw tissues held at -20°C. Cooked FUT and CMT were inoculated with two strain composites of either Salmonella or Listeria monocytogenes and held at 4 and 20OC. Salmonella enteritidis, Salmonella typhimurium, Q. monocytogenes Scott A, and a Q. monocytogenes meat isolate were organisms used in the inoculation studies. Aerobic and psychrotrophic counts were not different (p >0.05) at any sampling interval when numbers in raw EUT were compared to those in raw CMT. Coliform counts in raw FUT did not differ from those in raw CMT (p >0.05) after l day at 3°C. In inoculation studies, numbers of either pathogen generally did not differ (p >0.05) I between cooked FUT and CMT at selected sampling intervals. Salmonella counts declined gradually in cooked samples held at 4°C. By day 3, Salmonella levels increased more than 6 logs in tissues held at 20°C. L. monocytogenes counts increased approximately 5 logs in cooked FUT and CMT held at 4°C for 14 days. Numbers increased more than 5 logs in samples stored at 20°C for 48 hr. Although a significant (p <0.05) factor in some studies, color modification was not considered to have a major effect on microbial growth in altered thigh.