Food Safety Centre, Tasmanian Institute of Agriculture, University of Tasmania, Hobart TAS 7005, Australia.
Int J Food Microbiol. 2012 Jul 2;157(2):210-7. doi: 10.1016/j.ijfoodmicro.2012.05.007. Epub 2012 May 14.
Meat surfaces are contaminated with bacteria during slaughter and processing. Understanding bacterial attachment properties to specific structures of meat could result in more targeted interventions to improve its safety and quality. However, the influence of temperatures relevant to abattoir environments on bacterial attachment to specific meat structures is not known. In this study, the effect of temperature and protein concentration on attachment of 10 Escherichia coli and seven Salmonella strains to extracellular matrix (ECM) proteins (collagen I, fibronectin, collagen IV and laminin) was measured using crystal violet stain and epifluorescence microscopy assays. By crystal violet assay, only five of 17 strains showed significant attachment to any ECM protein and only one strain attached to all proteins. Strains that attached at all tested temperatures (4, 25, 37°C) were E. coli M23Sr and M23 (collagen I); E. coli M23Sr (fibronectin); E. coli M23Sr, O157:H12 and M23, (collagen IV); and E. coli M23Sr, O157:H12, O78:K80:H1, O26:H11 and M23 (laminin). A higher proportion of strains attached to basement membrane proteins (laminin and collagen IV) than to interstitial proteins (collagen I and fibronectin). Highest attachment levels occurred at 4°C for collagen I and at 25°C for the other three proteins. Generally, the attachment levels of Salmonella strains to all ECM proteins were lower than for E. coli. No significant effect was found for concentration of collagen I, fibronectin and collagen IV, but was for higher laminin concentration. A strong positive correlation was found between results of both the crystal violet and epifluorescent methods (r≥0.905, p<0.05). This study demonstrated that attachment properties to ECM proteins displayed distinct variation among strains, that temperature highly influenced attachment and that protein concentration had a minor effect.
肉在屠宰和加工过程中会被细菌污染。了解细菌对肉类特定结构的附着特性，可以有针对性地采取更多干预措施，以提高其安全性和质量。然而，屠宰环境相关温度对细菌附着到特定肉类结构的影响尚不清楚。在这项研究中，使用结晶紫染色和荧光显微镜检测法，测量了 10 株大肠杆菌和 7 株沙门氏菌菌株在不同温度和蛋白浓度下对细胞外基质（ECM）蛋白（胶原蛋白 I、纤连蛋白、胶原蛋白 IV 和层粘连蛋白）的附着情况。通过结晶紫检测法，只有 17 株菌中的 5 株对任何 ECM 蛋白有明显的附着作用，只有 1 株菌能附着所有蛋白。在所有测试温度（4、25、37°C）下均附着的菌株为大肠杆菌 M23Sr 和 M23（胶原蛋白 I）；大肠杆菌 M23Sr（纤连蛋白）；大肠杆菌 M23Sr、O157:H12 和 M23（胶原蛋白 IV）；以及大肠杆菌 M23Sr、O157:H12、O78:K80:H1、O26:H11 和 M23（层粘连蛋白）。与间质蛋白（胶原蛋白 I 和纤连蛋白）相比，更多的菌株附着在基底膜蛋白（层粘连蛋白和胶原蛋白 IV）上。胶原蛋白 I 的附着水平在 4°C 时最高，其他三种蛋白在 25°C 时最高。总体而言，沙门氏菌对所有 ECM 蛋白的附着水平均低于大肠杆菌。胶原蛋白 I、纤连蛋白和胶原蛋白 IV 的浓度对附着水平没有显著影响，但较高的层粘连蛋白浓度有影响。结晶紫和荧光法的结果之间存在很强的正相关（r≥0.905，p<0.05）。本研究表明，不同菌株对 ECM 蛋白的附着特性存在明显差异，温度对附着有很大影响，而蛋白浓度的影响较小。
