Bacteriocins for food safety

消费者对新鲜、最低限度加工、方便食品的需求导致冷藏、最低限度加工、不含防腐剂的食品供应大幅增加。冷藏是这些食品中食源性病原体生长和存活的唯一障碍，食源性疾病的暴发已有记录。乳酸菌产生抗菌肽，称为细菌素，它抑制与生产者菌株密切相关的生物体的生长。许多细菌素已经被提纯和鉴定，我们已经证明了细菌素在控制腐败和病原体的生长方面的有效性，例如冷藏食品中的单核细胞增生性李斯特菌。对更“天然”的食品防腐剂的日益重视，以及降低加工食品中钠浓度的举措，为细菌素在食品保存和安全方面创造了一个利基市场。 细菌素研究的障碍之一是缺乏检测食品中细菌素的方法。随着细菌素和细菌素产生菌在未来的使用范围扩大，进一步开发用于检测的灵敏分析技术的需求将会增加。我们利用基质辅助激光解吸/电离飞行时间质谱仪建立了培养上清液中细菌素的灵敏分析方法。到目前为止，我们还未能在食品中检测到II类细菌素的产生。这项拟议的研究旨在开发一种检测食品中细菌素产生的方法，并开发一种从食品基质中“捕获”细菌素的方法，然后进行分析。一旦这些方法被优化，它们将被用于监测食品中细菌素的生产。 由于细菌素在食品中的广泛应用，目标病原体对细菌素的适应性或耐药性已引起人们的关注。这项拟议的研究将确定不同菌株对细菌素的适应和耐药机制。 该项目将培训至少4名高素质的人员，有可能利用资金支持更多的人员。对高资质人员的培训将有助于填补加拿大食品微生物学研究人员的空白，并将满足食品加工行业对高资质人员的需求。

Consumer demand for fresh, minimally processed, convenient food products has resulted in a tremendous increase in the availability of refrigerated, minimally processed, preservative-free food products. Refrigeration is the only hurdle to the growth and survival of foodborne pathogens in these foods, and outbreaks of foodborne illness have been documented. Lactic acid bacteria produce antibacterial peptides, known as bacteriocins, which inhibit the growth of organisms closely related to the producer strain. Many bacteriocins have been purified and characterized, and we have demonstrated the effectiveness of bacteriocins to control the growth of spoilage and pathogenic organisms, such as Listeria monocytogenes in refrigerated foods. Increased emphasis on more “natural” food preservatives and the move to lower sodium concentrations in processed foods has created a niche for bacteriocins in food preservation and safety. One of the hurdles in research on bacteriocins is the lack of methods for detection of bacteriocins in food products. As the use of bacteriocins and bacteriocin-producing organisms expands in the future, the need for further development of sensitive analytical techniques for detection will increase. We developed a sensitive assay for bacteriocins in culture supernatants using a matrix-assisted laser desorption/ionization time-of-flight mass spectrometer. To date, we have not been able to detect the production of class II bacteriocins in foods. The proposed research aims to develop a method to detect the production of bacteriocins in food and to develop a method to “capture” the bacteriocins from the food matrix which can then be analyzed. Once these methods have been optimized, they will be used to monitor bacteriocin production in food products. The adaptation or resistance of target pathogens to bacteriocins has been raised as a concern for their widespread application in foods. The proposed research will determine the mechanisms of adaptation and resistance to bacteriocins for different strains of L. monocytogenes. The project will train at least 4 highly qualified individuals, with the potential for leveraging funds to support additional personnel. The training of highly qualified individuals will help fill the gaps in the availability of food microbiology researchers in Canada and will meet the needs of the food processing industry for highly qualified individuals.