University of Wisconsin-Madison, Food Research Institute, 1550 Linden Drive, Madison, Wisconsin 53706, USA.
J Food Prot. 2013 Dec;76(12):2074-8. doi: 10.4315/0362-028X.JFP-13-155.
Listeria monocytogenes growth can be controlled on ready-to-eat meats through the incorporation of antimicrobial ingredients into the formulation or by postlethality kill steps. However, alternate approaches are needed to provide options that reduce sodium content but maintain protection against pathogen growth in meats after slicing. The objective of this study was to determine the inhibition of L. monocytogenes by propionic acid-based ingredients in high-moisture, cured turkey stored at 4 or 7°C. Six formulations of sliced, cured (120 ppm of NaNO2 ), deli-style turkey were tested, including control without antimicrobials, 3.2% lactate-diacetate blend (LD), 0.4% of a liquid propionate-benzoate-containing ingredient, or 0.3, 0.4, and 0.5% of a liquid propionate-containing ingredient. Products were inoculated with 5 log CFU L. monocytogenes per 100-g package (3 log CFU/ml rinsate), vacuum-sealed, and stored at 4 or 7°C for up to 12 weeks; and populations were enumerated by plating on modified Oxford agar. As expected, the control without antimicrobials supported rapid growth, with >2 log average per ml rinsate increase within 4 weeks of storage at 4°C, whereas growth was observed at 6 weeks for the LD treatment. For both replicate trials, all treatments that contained liquid propionate or propionate-benzoate limited L. monocytogenes growth to an increase of <1 log through 9 weeks storage at 4°C. Sporadic growth (>1-log increase) was observed in individual samples for all propionate-containing treatments at weeks 10, 11, and 12. As expected, L. monocytogenes grew more rapidly when products were stored at 7°C, but trends in relative inhibition were similar to those observed at 4°C. These results verify that propionate-based ingredients inhibit growth of L. monocytogenes on sliced, high-moisture, cured turkey and can be considered as an alternative to reduce sodium-based salts while maintaining food safety.
李斯特菌的生长可以通过在配方中加入抗菌成分或通过后杀菌步骤来控制即食肉类。然而，需要采用替代方法来提供选项，以降低钠含量，但在切片后仍能保护肉类免受病原体生长的影响。本研究的目的是确定丙酸基成分对 4°C 或 7°C 储存的高水分、腌制火鸡肉中李斯特菌的抑制作用。测试了六种切片、腌制（120 ppm 的 NaNO2）、熟食风格火鸡肉的配方，包括不含抗菌剂的对照、3.2%的乳酸-双乙酸盐混合物（LD）、0.4%的液体丙酸盐-苯甲酸盐含成分，或 0.3、0.4 和 0.5%的液体丙酸盐含成分。产品用 5 log CFU L. monocytogenes 每 100 克包装（3 log CFU/ml 冲洗液）接种，真空密封，并在 4°C 或 7°C 下储存长达 12 周；通过在改良牛津琼脂上平板计数来计数种群。正如预期的那样，不含抗菌剂的对照支持快速生长，在 4°C 下储存 4 周内，每毫升冲洗液中平均增加>2 个对数，而 LD 处理则在 6 周时观察到生长。对于两个重复试验，所有含有液体丙酸或丙酸盐-苯甲酸盐的处理都将 L. monocytogenes 的生长限制在 4°C 下储存 9 周内增加<1 个对数。在 10、11 和 12 周时，所有含丙酸的处理在个别样品中都观察到了散发性生长（>1 个对数增加）。正如预期的那样，当产品在 7°C 下储存时，李斯特菌生长得更快，但抑制的趋势与在 4°C 下观察到的相似。这些结果验证了丙酸基成分可以抑制切片、高水分、腌制火鸡肉中李斯特菌的生长，可以作为减少基于钠的盐的替代方法，同时保持食品安全。
