Comparison of the Effect of Curing Ingredients Derived from Purified and Natural Sources on Inhibition of Outgrowth during Cooling of Deli-Style Turkey Breast

Abstract

The antimicrobial impact of purified and natural sources of both nitrite and ascorbate were evaluated against Clostridium perfringens during the postthermal processing cooling period of deli-style turkey breast. The objective of phase I was to assess comparable concentrations of nitrite (0 or 100 ppm) and ascorbate (0 or 547 ppm) from both purified and natural sources. Phase II was conducted to investigate concentrations of nitrite (50, 75, or 100 ppm) from cultured celery juice powder and ascorbate (0, 250, or 500 ppm) from cherry powder to simulate alternative curing formulations. Ground turkey breast (75% moisture, 1.2% salt, pH 6.2) treatments were inoculated with C. perfringens spores (three-strain mixture) to yield 2.5 log CFU/g. Individual 50-g portions were vacuum packaged, cooked to 71.1°C, and chilled from 54.4 to 26.7°C in 5 h and from 26.7 to 7.2°C in 10 additional hours. Triplicate samples were assayed for growth of C. perfringens at predetermined intervals by plating on tryptose-sulfite-cycloserine agar; experiments were replicated three times. In phase I, uncured, purified nitrite, and natural nitrite treatments without ascorbate had 5.3-, 4.2-, and 4.4-log increases in C. perfringens, respectively, at 15 h, but <1-log increase was observed at the end of chilling in treatments containing 100 ppm of nitrite and 547 ppm of ascorbate from either source. In phase II, 0, 50, 75, and 100 ppm of nitrite and 50 ppm of nitrite plus 250 ppm of ascorbate supported 4.5-, 3.9-, 3.5-, 2.2-, and 1.5-log increases in C. perfringens, respectively. In contrast, <1-log increase was observed after 15 h in the remaining phase II treatments supplemented with 50 ppm of nitrite and 500 ppm of ascorbate or ≥75 ppm of nitrite and ≥250 ppm of ascorbate. These results confirm that equivalent concentrations of nitrite, regardless of the source, provide similar inhibition of C. perfringens during chilling and that ascorbate enhances the antimicrobial effect of nitrite on C. perfringens at concentrations commonly used in alternative cured meats.

Impact of Clean-Label Antimicrobials and Nitrite Derived from Natural Sources on the Outgrowth of Clostridium perfringens during Cooling of Deli-Style Turkey Breast

“…In addition, results of this study validate that >50 ppm of nitrite plus I. 0% FE or CSV provided sufficient inhibition of C. perfringens to allow for safe chilling of deli-style turkey breast over 15 h, following the critical parameters outlined in FSIS Appendix B. Supplementing purified or natural nitrite with ascorbate, a cure accelerator from purified and natural (cherry powder) sources, has been demonstrated to be a viable option to inhibit growth of C. perfringens during extended chilling (16). Along with ascorbate, the results of this study provide additional options for meat processors to incorporate adjunct ingredients and safely chill alternative cured products.…”

“…Conversely, the antimicrobial impact observed with the relatively low nitrite concentration included in this study can be increased with the addition of an antimicrobial. It is important to note that the treatments evaluated in this study did not contain ascorbate, which likely would have further enhanced the observed inhibition in treatments containing nitrite (16). Jackson et al (9) also reported variability between clean-label antimicrobial ingredients, based on their in hibitory effects against C. perfringens when used in formulations with natural sources of nitrite.…”

“…For this experiment, the pH of the FE treatment was adjusted to match that of an uncured control (no antimicrobial included), and similar testing procedures were followed as previously outlined, except samples were enumerated at 0, 5, and 10 h following the same 15-h cooling curve. In previous studies, little population change was observed between 10 and 15 h, and the objective of this study was to elucidate differences between the treatments, not to validate the 15-h cooling curve (16). The treatments, analyzed pH values, and changes in C. perfringens populations during chilling are presented in Table 4.…”

“…offered an additive or synergistic effect when used with these antimicrobials, each antimicrobial was tested alone and in combination with 50 ppm of nitrite from cultured celery juice powder, a usage level typically found in alternative cured formulations and shown to provide minimal growth inhibition when used alone (16).…”

“…Jackson et al (10) reported that during 10 days of storage at 20°C, alternative cured frankfurters (ingoing nitrite concentration not known) inoculated with C. perfringens allowed for ~4.7-log increase, whereas conventionally cured controls (156 ppm of ingoing nitrite) permitted ~ 1.7-log increase. A recently completed study in our laboratory revealed that alternative cured products containing nitrite from cultured celery juice powder (50, 75, or 100 ppm) allowed outgrowth of > 1 log during 15 h of chilling, but supplementation with cherry powder, a natural source of ascorbic acid, improved the antimicrobial impact of nitrite and inhibited C. perfringens outgrowth (16).…”