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

Combination treatment processes for the microbial decontamination of pork t rim were developed and evaluated. Lean pork trim tissue (LPT) and fat-cover ed pork trim tissue (FPT) inoculated with swine feces were treated with int ervention processes as follows: (i) control (untreated), (ii) water (15 deg reesC, 120 s), (iii) water followed by lactic acid wash (15 degreesC, 75 s) , (iv) combination 1 (water plus hot water [65.5 degreesC, 15 s] plus hot a ir [510 degreesC, 60 s] plus lactic acid), (v) combination 2 (water plus ho t water [82.2 degreesC, 15 s] plus hot air [510 degreesC, 75 s] plus lactic acid), and (vi) combination 3 (water plus hot water [82.2 degreesC, 45 s] plus hot air [510 degreesC, 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 degreesC storage. Regardless of the intervention treatment, lower m icrobial populations were observed on FPT than on LPT immediately after tre atment and during the 7-day storage period. Both LPT and FPT treated with w ater plus lactic acid, combination i, combination 2, and combination 3 had lower remaining populations of all microbial groups immediately after treat ment than did water-treated samples, Populations of aerobic bacteria, colif orms, E. coli, and lactic acid bacteria on either LPT or FPT did not statis tically increase during the 7-day storage period. On LPT, populations of ps ychrotrophic bacteria grew during 4 degreesC storage but remained lower at day 7 on LPT treated by combinations 2 and 3 (2.29 and 1.89 log(10) CFU/cm( 2), respectively) than on LPT treated with water (4.07 log(10) CFU/cm(2)) o r water plus lactic acid (3.52 log(10) CFU/cm(2)). Populations of psychrotr ophic bacteria remained below detectable levels throughout the 7-day storag e on FPT treated with water plus lactic acid or any of the three combinatio n 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 treat ments in reducing microbial populations on pork trim without affecting the quality attributes of the ground pork.