Evaluation of combination treatment processes for the microbial decontamination of pork trim

Combination treatment processes for the microbial decontamination of pork trim were developed and evaluated. Lean pork trim tissue (LPT) and fat-covered pork trim tissue (FPT) inoculated with swine feces were treated with intervention processes as follows: (i) control (untreated), (ii) water (15 degrees C, 120 s), (iii) water followed by lactic acid wash (15 degrees C, 75 s), (iv) combination 1 (water plus hot water [65.5 degrees C, 15 s] plus hot air [510 degrees C, 60 s] plus lactic acid), (v) combination 2 (water plus hot water [82.2 degrees C, 15 s] plus hot air [510 degrees C, 75 s] plus lactic acid), and (vi) combination 3 (water plus hot water [82.2 degrees C, 45 s] plus hot air [510 degrees C, 90 s] plus lactic acid). Populations of aerobic bacteria, psychrotrophic bacteria, coliforms, Escherichia coli, and lactic acid bacteria were determined before and after treatment and at days 2 and 7 of 4 degrees C storage. Regardless of the intervention treatment, lower microbial populations were observed on FPT than on LPT immediately after treatment and during the 7-day storage period. Both LPT and FPT treated with water plus lactic acid, combination 1, combination 2, and combination 3 had lower remaining populations of all microbial groups immediately after treatment than did water-treated samples. Populations of aerobic bacteria, coliforms, E. coli, and lactic acid bacteria on either LPT or FPT did not statistically increase during the 7-day storage period. On LPT, populations of psychrotrophic bacteria grew during 4 degrees C storage but remained lower at day 7 on LPT treated by combinations 2 and 3 (2.29 and 1.89 log10 CFU/cm2, respectively) than on LPT treated with water (4.07 log10 CFU/cm2) or water plus lactic acid (3.52 log10 CFU/cm2). Populations of psychrotrophic bacteria remained below detectable levels throughout the 7-day storage on FPT treated with water plus lactic acid or any of the three combination treatments. Treatment of pork trim with any of the combination treatments significantly (P < 0.05) affected the color and emulsion stability of the ground pork. Water and water plus lactic acid were the most favorable treatments in reducing microbial populations on pork trim without affecting the quality attributes of the ground pork.