Institute for Agricultural and Fisheries Research, ILVO, Technology and Food Science Unit, Brusselsesteenweg 370, 9090 Melle, Belgium.
Int J Food Microbiol. 2011 Jan 31;145(1):43-8. doi: 10.1016/j.ijfoodmicro.2010.11.023. Epub 2010 Nov 23.
Chitosan is a biopolymer with antimicrobial activity and film-forming properties. In this study, the effects on Salmonella shell contamination and trans-shell penetration of coating hens' eggs with chitosan was evaluated. A chitosan was selected from eight types (four non-commercial and four commercial) based on its antimicrobial activity against Salmonella enterica serovar Enteritidis (S. Enteritidis). For this purpose, a contact plate method was developed and chitosans were applied at a concentration of 0.25% (w/v). A commercial type with a molecular weight of 310-375 kDa and a deacetylation degree of 75% that reduced S. Enteritidis by 0.71 log(10) colony forming units compared to the control (without chitosan) was selected for further studies. The chitosan was shown to have antimicrobial activity against other egg borne bacteria, i.e., Acinetobacter baumannii, Alcaligenes sp., Carnobacterium sp., Pseudomonas sp., Serratia marcescens and Staphylococcus warneri, and against S. enterica serovar Typhimurium, Escherichia coli and Listeria monocytogenes. The effects of various concentrations of the selected chitosan (0.25%, 1% and 2%) on Salmonella shell contamination and trans-shell penetration were assessed using the agar molding technique. Effective reduction of eggshell contamination could not be demonstrated, but trans-shell penetration was significantly reduced in the presence of a 2% chitosan eggshell coating, with only 6.1% of the eggs being penetrated compared to 24.5% of the uncoated eggs. It was concluded that the 2% chitosan coating has the potential to reduce contamination of egg contents resulting from trans-shell penetration by S. Enteritidis.
壳聚糖是一种具有抗菌活性和成膜性能的生物聚合物。本研究评估了壳聚糖对鸡蛋壳表面污染和穿透蛋壳的影响。根据其对肠炎沙门氏菌（S. Enteritidis）的抗菌活性，从 8 种壳聚糖（4 种非商业和 4 种商业）中选择了一种壳聚糖。为此，开发了一种接触平板法，并将壳聚糖应用于 0.25%（w/v）的浓度。选择了一种商业类型，其分子量为 310-375 kDa，脱乙酰度为 75%，与对照组（无壳聚糖）相比，可将肠炎沙门氏菌减少 0.71 log(10)菌落形成单位，用于进一步研究。壳聚糖对其他鸡蛋携带的细菌，即鲍曼不动杆菌、产碱菌、食酸菌、假单胞菌、粘质沙雷氏菌和华纳葡萄球菌，以及肠炎沙门氏菌、大肠杆菌和单核细胞增生李斯特菌均具有抗菌活性。采用琼脂成型技术评估了所选壳聚糖（0.25%、1%和 2%）对沙门氏菌蛋壳污染和穿透蛋壳的影响。虽然不能证明有效减少蛋壳污染，但在 2%壳聚糖蛋壳涂层的存在下，穿透蛋壳的情况明显减少，只有 6.1%的鸡蛋被穿透，而未涂层的鸡蛋有 24.5%被穿透。结论是，2%壳聚糖涂层有可能减少肠炎沙门氏菌穿透蛋壳对蛋内容物的污染。
