Univ. Bourgogne Franche-Comté, AgroSup Dijon, PAM UMR A 02.102, F-21000, Dijon, France.
Laboratory of Epidemiology and Veterinary Microbiology, Group of Bacteriology and Biotechnology, Pasteur Institute of Tunisia (IPT), Tunisia, BP 74, 13 Place Pasteur, Belvédère, 1002, Tunis, University Tunis El Manar, Tunisia.
Food Microbiol. 2019 Dec;84:103244. doi: 10.1016/j.fm.2019.103244. Epub 2019 Jun 17.
Today, there is no effective non-thermal method to inactivate unwanted bacterial spores in foods. High-Pressure (HP) process has been shown to act synergistically with moderate heating and the bacteriocin nisin to inactivate spores but the mechanisms have not been elucidated. The purpose of the present work was to investigate in depth the synergy of HP and nisin on various foodborne spore species and to bring new elements of understandings. For this purpose, spores of Bacillus pumilus, B. sporothermodurans, B. licheniformis, B. weihenstephanensis, and Clostridium sp. were suspended in MES buffer, in skim milk or in a liquid medium simulating cooked ham brine and treated by HP at 500 MPa for 10 min at 50 °C or 20 °C. Nisin (20 or 50 IU/mL) was added at three different points during treatment: during HP, during and or in the plating medium of enumeration. In the latter two cases, a high synergy was observed with the inhibition of the spores of Bacillus spp. The evaluation of the germinated fraction of Bacillus spp. spores after HP revealed that this synergy was likely due to the action of nisin on HP-sensitized spores, rather than on HP-germinated spores. Thus, the combination of nisin and HP can lead to Bacillus spp. spore inhibition at 20 °C. And Nisin can act on HP-treated spores, even if they are not germinated. This paper provides new information about the inhibition of spores by the combination of HP and nisin. The high synergy observed at low temperature has not been reported yet and could allow food preservation without the use of any thermal process.
目前，在食品中没有有效且非热的方法来使不需要的细菌孢子失活。已证明高压（HP）工艺与适度加热和抑菌素乳链菌肽协同作用以灭活孢子，但机制尚未阐明。本研究的目的是深入研究 HP 和乳链菌肽对各种食源孢子的协同作用，并提供新的理解。为此，将枯草芽孢杆菌、B. sporothermodurans、B. licheniformis、B. weihenstephanensis 和梭状芽孢杆菌的孢子悬浮在 MES 缓冲液、脱脂乳或模拟煮火腿盐水的液体培养基中，并在 50°C 或 20°C 下用 500 MPa 的 HP 处理 10 分钟。在处理过程中，乳链菌肽（20 或 50IU/mL）在三个不同点添加：在 HP 期间、在 HP 期间和/或在计数的平板培养基中添加。在后两种情况下，观察到与芽孢杆菌属孢子的高度协同作用。对 HP 后芽孢杆菌属孢子发芽部分的评估表明，这种协同作用可能是由于乳链菌肽对 HP 敏感的孢子的作用，而不是对 HP 发芽的孢子的作用。因此，乳链菌肽和 HP 的组合可以在 20°C 下抑制芽孢杆菌属孢子。并且乳链菌肽可以作用于 HP 处理的孢子，即使它们没有发芽。本文提供了关于 HP 和乳链菌肽联合抑制孢子的新信息。在低温下观察到的高协同作用尚未报道，这可能允许在不使用任何热过程的情况下进行食品保存。
