Muhandiramlage Gayani Kuriyawe, McWhorter Andrea R, Chousalkar Kapil K
School of Animal and Veterinary Sciences, University of Adelaide, Adelaide, SA, Australia.
Front Microbiol. 2020 Mar 25;11:503. doi: 10.3389/fmicb.2020.00503. eCollection 2020.
Broiler chickens frequently become colonized by species. As a consequence, , can enter the poultry meat supply chain and represents a significant risk for human public health. A number of on-farm biosecurity and processing measures are used to mitigate the load of on chicken meat. In many countries, chlorine is commonly used as a biocide in processing plants to reduce bacterial loads on poultry carcasses but there is limited evidence of its effectiveness on . In this study, 116 isolates (89 and 27 ) were isolated from poultry meat carcasses prior to the inside/outside wash step and used in assays exploring the efficacy of chlorine. A high proportion of isolates exhibited MIC and MBC values of 128 ppm but organic material present in the broth likely affected this result. Thus, additional bactericidal assays (time kill and chlorine inactivation) were used to characterize the response of isolates to different concentrations of chlorine. At 10 CFU, was found to be highly sensitive to concentrations of chlorine and was inhibited at low concentrations (0.2-2.0 ppm). At a higher bacterial load (10 CFU), variation in the response of different isolates was observed. One isolate was growth inhibited at 1.8 ppm while another required 16 ppm. At 10 CFU, could be resuscitated following exposure to chlorine highlighting a potential limitation of chlorine use. Analysis of UV leakage indicated that high chlorine concentrations resulted in increased 280 nm absorbance values suggesting bacterial membrane damage. Scanning electron and transmission electron microscopy were performed to characterize the morphological effects of chlorine exposure. Some effects of chlorine exposure included changes in shape (coccoid, or elongated), cellular degeneration, and shriveled bacterial cells. Interestingly, with normal morphology were also observed in the chlorine exposed group and represent a population of cells that could be resuscitated. This study is useful for the chicken meat industry and provides data for future optimization of chlorine use in reducing loads.
肉鸡经常被某些物种定植。因此，这些物种可进入禽肉供应链，并对人类公共健康构成重大风险。一些农场生物安全和加工措施被用于减轻鸡肉上这些物种的负荷。在许多国家，氯通常在加工厂用作杀菌剂以减少家禽胴体上的细菌负荷，但关于其对这些物种有效性的证据有限。在本研究中，在内部/外部清洗步骤之前从禽肉胴体中分离出116株这些物种的分离株（89株[具体物种未提及]和27株[具体物种未提及]），并用于探索氯功效的试验。高比例的分离株表现出最低抑菌浓度（MIC）和最低杀菌浓度（MBC）值为128 ppm，但肉汤中存在的有机物质可能影响了这一结果。因此，使用了额外的杀菌试验（时间杀灭和氯灭活）来表征这些物种分离株对不同浓度氯的反应。在10⁶CFU时，发现这些物种对氯浓度高度敏感，并在低浓度（0.2 - 2.0 ppm）下受到抑制。在更高的细菌负荷（10⁸CFU）下，观察到不同这些物种分离株反应的差异。一株分离株在1.8 ppm时生长受到抑制，而另一株则需要16 ppm。在10⁹CFU时，这些物种在接触氯后可以复苏，这突出了氯使用的一个潜在局限性。紫外线泄漏分析表明，高氯浓度导致280 nm吸光度值增加，表明细菌膜受损。进行扫描电子显微镜和透射电子显微镜以表征氯暴露的形态学影响。氯暴露的一些影响包括形状变化（球状或拉长）、细胞变性和细菌细胞皱缩。有趣的是，在氯暴露组中也观察到形态正常的这些物种，它们代表了可以复苏的细胞群体。本研究对鸡肉行业有用，并为未来优化氯在减少这些物种负荷方面的使用提供了数据。
