University of Alberta, Dept. of Agricultural, Food and Nutritional Science, Edmonton, Canada.
University of Alberta, Dept. of Agricultural, Food and Nutritional Science, Edmonton, Canada; Hubei University of Technology, College of Bioengineering and Food Science, Wuhan, PR China.
Int J Food Microbiol. 2019 Feb 2;290:68-75. doi: 10.1016/j.ijfoodmicro.2018.10.003. Epub 2018 Oct 4.
The aim of this study was to investigate the synergistic effect of chitosan and bacteriocins against Escherichia coli and Salmonella in media and in lean beef. The inhibitory effects of chitosan and bacteriocins against E. coli AW1.7 and S. enterica Typhimurium in media were determined by a critical dilution assay. The efficacy a bacteriocin-producing strain of Carnobacterium maltaromaticum and high molecular weight chitosan (HMWC) in inactivation of E. coli AW1.7 and S. Typhimurium was evaluated on beef. Current interventions applied in the beef industry, steaming coupled with lactic acid, were used as reference. HMWC demonstrated higher antibacterial activity than water soluble chitosan (WSC) or chitosan oligosaccharides (COS) in media, and the addition of partially purified bacteriocins from C. maltaromaticum UAL307 increased the activity of the chitosan in vitro. The hurdle combinations associated with HMWC inactivated E. coli AW1.7 and S. enterica Typhimurium more effectively on lean beef when compared to steam or steam coupled with lactic acid. When used on beef, addition of bacteriocins and chitosan did not increase the antibacterial efficacy. Cell counts of S. enterica were further reduced during storage in presence of C. maltaromaticum and chitosan; however, this decrease was not dependent on bacteriocin production. In conclusion, addition of chitosan alone or in combination with C. maltaromaticum UAL 307 as protective culture significantly reduces cell counts of E. coli and Salmonella on beef. Results will be useful to improve pathogen intervention treatments in beef processing.
本研究旨在探讨壳聚糖与细菌素在培养基和瘦牛肉中对大肠杆菌和沙门氏菌的协同作用。通过临界稀释试验测定壳聚糖和细菌素对培养基中大肠杆菌 AW1.7 和肠炎沙门氏菌 Typhimurium 的抑制作用。评价了产细菌素的马尔他乳杆菌和高分子量壳聚糖（HMWC）对牛肉中大肠杆菌 AW1.7 和肠炎沙门氏菌的灭活效果。目前应用于牛肉工业的干预措施，如蒸煮结合乳酸，被用作参考。在培养基中，HMWC 比水溶性壳聚糖（WSC）或壳聚糖寡糖（COS）具有更高的抗菌活性，并且添加来自马尔他乳杆菌 UAL307 的部分纯化细菌素增加了壳聚糖的体外活性。与 HMWC 相关的障碍组合在瘦牛肉上比蒸汽或蒸汽结合乳酸更有效地灭活大肠杆菌 AW1.7 和肠炎沙门氏菌。当用于牛肉时，添加细菌素和壳聚糖并没有增加抗菌效果。在存在马尔他乳杆菌和壳聚糖的情况下，肠炎沙门氏菌的细胞计数在储存过程中进一步降低；然而，这种减少并不依赖于细菌素的产生。总之，单独添加壳聚糖或与 C. maltaromaticum UAL 307 联合添加作为保护培养物可显著降低牛肉中大肠杆菌和沙门氏菌的细胞计数。研究结果将有助于改善牛肉加工中病原体干预处理。
