Allison Abimbola, Fouladkhah Aliyar Cyrus
Public Health Microbiology Laboratory, Tennessee State University, Nashville, Tennessee, United States of America.
PLoS One. 2021 Feb 18;16(2):e0246735. doi: 10.1371/journal.pone.0246735. eCollection 2021.
Various serogroups of Shiga toxin-producing Escherichia coli have been epidemiologically associated with foodborne disease episodes in the United States and around the globe, with E. coli O157: H7 as the dominant serogroup of public health concern. Serogroups other than O157 are currently associated with about 60% of Shiga toxin-producing E. coli related foodborne illness episodes. Current study evaluated sensitivity of the O157 and epidemiologically important non-O157 serogroups of the pathogen to elevated hydrostatic pressure and 1% lactic acid. Pressure intensity of 250 to 650 MPa were applied for 0 to 7 min for inactivation of strain mixtures of wild-type and rifampicin-resistant E. coli O157, as well as O26, O45, O103, O111, O121, and O145 serogroups and ATCC® 43895™ strain in ground meat and 10% meat homogenate. E. coli O157 were reduced (p < 0.05) from 6.86 ± 0.2 to 4.56 ± 0.1 log CFU/g when exposed to pressure of 650 MPa for 7 min. Corresponding reductions (p < 0.05) for non-O157 E. coli were from 6.98 ± 0.3 to 4.72 ± 0.1. The D-values at 650 MPa were 3.71 and 3.47 min for O157 and non-O157 serogroups, respectively. Presence of 1% lactic acid to a great extent augmented (p < 0.05) decontamination efficacy of the treatment in meat homogenate resulting in up to 5.6 and 6.0 log CFU/mL reductions for O157 and non-O157 serogroups, respectively. Among the tested serogroups, the wild-type and rifampicin-resistant phenotypes exhibited (p ≥ 0.05) comparable pressure sensitivity. Thus, these two phenotypes could be used interchangeably in validation studies. Our results also illustrate that, application of elevated hydrostatic pressure could be utilized for assuring safety of ground and non-intact meat products against various serogroups of Shiga toxin-producing E. coli. Addition of 1% lactic acid additionally provided industrially appreciable augmentation in efficacy of the pressure-based treatments.
在美国和全球范围内，各种产志贺毒素大肠杆菌血清型在流行病学上与食源性疾病暴发相关，其中大肠杆菌O157:H7是引起公共卫生关注的主要血清型。目前，除O157外的其他血清型与约60%的产志贺毒素大肠杆菌相关食源性疾病暴发有关。当前研究评估了该病原体的O157血清型以及具有重要流行病学意义的非O157血清型对高静水压和1%乳酸的敏感性。对野生型和耐利福平的大肠杆菌O157以及O26、O45、O103、O111、O121和O145血清型的菌株混合物，以及美国典型培养物保藏中心（ATCC）43895™菌株，在绞碎肉和10%肉匀浆中施加250至650兆帕的压力强度0至7分钟，以使其失活。当暴露于650兆帕压力7分钟时，大肠杆菌O157的数量从6.86±0.2 log CFU/g降至4.56±0.1 log CFU/g（p<0.05）。非O157大肠杆菌的相应减少量（p<0.05）为从6.98±0.3降至4.72±0.1。在650兆帕压力下，O157和非O157血清型的D值分别为3.71分钟和3.47分钟。在肉匀浆中添加1%乳酸在很大程度上增强了（p<0.05）处理的去污效果，使O157和非O157血清型的数量分别减少多达5.6和6.0 log CFU/mL。在测试的血清型中，野生型和耐利福平表型表现出（p≥0.05）相当的压力敏感性。因此，这两种表型可在验证研究中互换使用。我们的结果还表明，施加高静水压可用于确保绞碎肉和非完整肉制品对各种产志贺毒素大肠杆菌血清型的安全性。添加1%乳酸还在工业上显著增强了基于压力处理的效果。
