Efficacy of natural antimicrobial systems used in foods; bacterial stress response and mode of action.

根据加拿大食品检验局的数据，每年有1100万例食源性疾病。被大肠杆菌O157:H7污染的碎牛肉在2012年秋季成为新闻头条。此外，肉类和肉制品仍然是最常与食源性疾病联系在一起的食物。消费者对方便、最低限度加工、更安全、保质期延长的食品的需求，已成为开发提高食品微生物质量和安全新策略的推动力。在挑战和保质期研究期间，我们的实验室已经成功地研究了从植物中提取的天然抗菌剂，如多酚化合物，用于动物饲料（牛至油和蔓越莓果肉）和加工肉类配方（百里香精油）。除了细胞计数和对数减少之外，我们必须在分子水平上了解与这些新的天然抗菌剂相关的作用机制和耐药性。因此，利用PCR分析和微阵列技术，将研究暴露于天然抗菌剂（尤其是百里香洋葱提取物精油、nisin等）的靶细胞（大肠杆菌、单核增生李斯特菌、梭状芽胞杆菌等）中的基因表达。这种分子分析将允许更有效地选择抗菌药物组合治疗。从长远来看，让植物和动物生产部门共同参与减少浪费和腐败，同时提高食品安全，对我们的农业食品部门来说是一种更可持续的方法。这将对其社会经济增长产生积极影响，并通过减少食源性疾病暴发对公共卫生产生积极影响。

According to the Canadian Food Inspection Agency, there are 11 million cases of food borne illnesses every year. Ground beef contaminated with Escherichia coli O157:H7 made the news headlines in the fall of 2012. Furthermore, meat and meat products remain the type of foods most often associated with food borne illnesses. Consumer demands for convenient, minimally processed, safer foods with extended shelf life have been a driving force in the development of new strategies to improve food microbial quality and safety. Natural antimicrobials, such as polyphenolic compounds extracted from plants have been successfully studied in our laboratory for that purpose both in animal feed (oregano oil and cranberry pulpe) and in processed meat formulations (thyme essential oil) during challenge and shelf life studies. Beyond cell enumeration and log reductions, we must understand the mechanism of action and resistance associated with these new natural antimicrobials at the molecular level. Hence, using PCR analysis and microarray technology, gene expression in target cells (Escherichia coli, Listeria monocytogenes, Clostridium, etc.) will be studied upon exposition to natural antimicrobial notably essential oil of thyme onion extract, nisin, etc. This molecular analysis will allow a more effective selection of antimicrobial combination of treatments. In the long run, having the plant and animal production sectors involved together in reducing waste and spoilage while improving food safety, is a more sustainable approach for our agri-food sector. This will have a positive impact on its socio-economic growth, and on public health through the reduction of food borne outbreaks.