The growing demand for minimally processed foods with clean labels has stimulated research into mild processing methods and natural antimicrobials to replace intensive heating and conventional preservatives, respectively. However, we have previously demonstrated that repetitive exposure of some bacteria to mild heat or subinhibitory concentrations of essential oil constituents (EOCs) may induce the emergence of mutants with increased resistance to these treatments. Since the combination of mild heat with some EOCs has a synergistic effect on microbial inactivation, we evaluated the potential of such combinations against our resistant E. coli mutants. While citral, carvacrol and t-cinnamaldehyde synergistically increased heat inactivation (53.0 °C, 10 min) of the wild-type MG1655 suspended in buffer, only the combination with carvacrol (200 μl/l) was able to mitigate the increased resistance of all the mutants. Moreover, the combination of heat and carvacrol acted synergistically inactivating heat-resistant variants of E. coli O157:H7 (ATCC 43888). This combined treatment could synergistically achieve more than 5 log10 reductions of the most resistant mutants in coconut water, although the temperature had to be raised to 57.0 °C. Therefore, the combination of mild heat with carvacrol appears to hold promise for mild processing, and it is expected to counteract the development of heat resistance.

中文翻译：

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结合温和的热量和植物精油成分，可以使缓冲液和椰子水中的大肠杆菌抗性变体失活。

对带有清洁标签的最低限度加工食品的需求不断增长，刺激了人们对温和加工方法和天然抗菌剂的研究，以分别代替集中加热和常规防腐剂。但是，我们以前已经证明，某些细菌反复暴露于温和的热或亚抑制浓度的精油成分（EOC）可能会导致突变体的出现，这些突变体对这些处理的抵抗力会增强。由于温和热与某些EOC的组合对微生物失活具有协同作用，因此我们评估了此类组合针对我们的耐药性E. coli突变体的潜力。柠檬醛，香芹酚和叔肉桂醛协同增加悬浮在缓冲液中的野生型MG1655的热失活（53.0°C，10分钟），只有与香芹酚（200μl/ l）的组合才能减轻所有突变体的抗药性。此外，热量和香芹酚的组合可协同灭活大肠杆菌O157：H7（ATCC 43888）的耐热变异体。尽管必须将温度升高到57.0°C，但这种联合处理可以协同作用使椰子水中最具抗性的突变体减少5 log10以上。因此，温和的热量与香芹酚的组合似乎有望实现温和的加工，并且有望抵消耐热性的发展。尽管必须将温度升高到57.0°C，但这种联合处理可以协同作用使椰子水中最具抗性的突变体减少5 log10以上。因此，温和的热量与香芹酚的组合似乎有望实现温和的加工，并且有望抵消耐热性的发展。尽管必须将温度升高到57.0°C，但这种联合处理可以协同作用使椰子水中最具抗性的突变体减少5 log10以上。因此，温和的热量与香芹酚的结合似乎有望实现温和的加工，并且有望抵消耐热性的发展。