Abstract Suspensions of non-pathogenic Listeria innocua ATCC 33090 in water were exposed to different combinations of high hydrostatic pressure (HPP), pulsed electric field (PEF) and sonication treatments. Treatments were conducted individually, or in various combinations – sequential HPP-PEF; sequential PEF-HPP, simultaneous HPP-PEF, sequential HPP-sonication and sequential sonication-HPP. The greatest reduction by an individual treatment was obtained with HPP, wherein exposure to 400 MPa for 100 s resulted in an 8 log reduction in CFU. Both PEF (30 kV, 10−3 s) and sonication (250s) treatments gave about 2 log reduction in the Listeria population. Sequentially applied HPP-PEF, and PEF-HPP treatments demonstrated mostly additive effects. Notably, however, a synergistic effect was observed when PEF and HPP were applied simultaneously. Combinations of HPP and sonication treatments demonstrated synergistic effects when HPP treatment was followed by sonication, but additive effects when sonication was followed by HPP. A relationship between Listeria innocua inactivation and increase in the suspension zeta potential was observed. However, protein content of the supernatant was found insignificant, indicating that leakage from cells were non-protein cell constituents.

中文翻译：

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联合高压 (HPP)、脉冲电场 (PEF) 和超声处理对无害李斯特菌灭活的影响

摘要 将水中的非致病性无害李斯特菌 ATCC 33090 悬浮液暴露于高静水压 (HPP)、脉冲电场 (PEF) 和超声处理的不同组合。治疗是单独进行的，或以各种组合进行——顺序 HPP-PEF；顺序 PEF-HPP、同时 HPP-PEF、顺序 HPP 超声处理和顺序超声处理-HPP。使用 HPP 获得了单个处理的最大降低，其中暴露于 400 MPa 100 秒导致 CFU 降低 8 log。PEF（30 kV，10-3 秒）和超声处理（250 秒）均使李斯特菌种群减少了约 2 log。依次应用的 HPP-PEF 和 PEF-HPP 处理主要表现出累加效应。然而，值得注意的是，当同时应用 PEF 和 HPP 时，观察到了协同效应。HPP 和超声处理的组合在 HPP 处理之后进行超声处理时表现出协同作用，但在超声处理之后进行 HPP 时表现出累加效应。观察到无害李斯特菌灭活和悬浮 zeta 电位增加之间的关系。然而，发现上清液的蛋白质含量微不足道，表明从细胞中渗漏的是非蛋白质细胞成分。