Leroi Françoise, Cornet Josiane, Chevalier Frédérique, Cardinal Mireille, Coeuret Gwendoline, Chaillou Stéphane, Joffraud Jean-Jacques
Ifremer, Laboratoire Ecosystèmes Microbiens et Molécules Marines pour les Biotechnologies (EM3B), BP 21105, 44311 Nantes, France.
Ifremer, Laboratoire Bioressources Marines et Bioraffinerie par hydrolyse enzymatique (BIORAF HE), BP 21105, 44311 Nantes, France.
Int J Food Microbiol. 2015 Nov 20;213:79-87. doi: 10.1016/j.ijfoodmicro.2015.05.005. Epub 2015 May 14.
Biopreservation is a natural technology of food preservation, which consists of inoculating food with microorganisms selected for their antibacterial properties. The objective of this study was to select lactic acid bacteria (LAB) to improve the quality of cold-smoked salmon (CSS). In this work, different strains representative of the 4 dominant species, identified in a previous study by pyrosequencing the 16S rRNA gene, were isolated and their spoiling potential in CSS blocks, sterilized by ionization, was assessed by twelve trained panelists along the vacuum storage at 8°C. Photobacterium phosphoreum, Brochothrix thermosphacta and Serratia proteamaculans released strong off-odors whereas the spoiling potential of Carnobacterium divergens was weaker. The spoiling capacity of Lactococcus piscium EU2241, Leuconostoc gelidum EU2247, Lactobacillus sakei EU2885, Staphylococcus equorum S030674 and 4 commercial starters was tested by the same method and 2 strains were eliminated due to off-odor production. The effect of the 6 selected LAB against the 4 specific spoiling organisms (SSOs) selected was tested by challenge tests in sterile CSS blocks. The protective effect of the LAB differed from one SSO to another and no correlation could be established between the sensory improvement, SSO inhibition, and the implantation or acidification of protective cultures (PCs). All the PCs except L. piscium reduced the off-odors released by P. phosphoreum although some of them had no effect on its growth. S. equorum, which did not grow in CSS, favored the implantation of P. phosphoreum but prevented its off-odor formation. L. piscium was the only strain that prevented the spoilage of B. thermosphacta and S. proteamaculans although it did not grow very well and did not acidify the product. L. gelidum EU2247 inhibited the growth of these 2 SSOs and lowered the pH but had no effect on the sensory quality. Finally, L. piscium was tested in 2 naturally contaminated products, with a positive effect on 1 batch. This effect was not correlated with the microbial ecosystem as determined by acultural and cultural techniques. Based on these results, the selection strategy is discussed.
生物保鲜是一种天然的食品保鲜技术，它包括用具有抗菌特性的微生物接种食品。本研究的目的是选择乳酸菌（LAB）来提高冷熏三文鱼（CSS）的品质。在这项工作中，分离出了先前通过对16S rRNA基因进行焦磷酸测序鉴定出的4个优势种的不同代表性菌株，并由12名经过培训的评审员在8°C真空储存条件下评估它们在经电离灭菌的CSS块中的腐败潜力。磷发光杆菌、嗜热栖热放线菌和变形斑沙雷氏菌释放出强烈的异味，而分歧肉杆菌的腐败潜力较弱。采用相同方法测试了鱼乳球菌EU2241、嗜冷明串珠菌EU2247、清酒乳杆菌EU2885、马胃葡萄球菌S030674和4种商业发酵剂的腐败能力，由于产生异味淘汰了2个菌株。通过在无菌CSS块中进行挑战试验，测试了6种选定的LAB对4种选定的特定腐败菌（SSO）的效果。LAB的保护作用因不同的SSO而异，在感官改善、SSO抑制以及保护性培养物（PC）的植入或酸化之间无法建立相关性。除鱼乳球菌外，所有的PC都减少了磷发光杆菌释放的异味，尽管其中一些对其生长没有影响。在CSS中不生长的马胃葡萄球菌有利于磷发光杆菌的植入，但阻止了其异味的形成。鱼乳球菌是唯一能防止嗜热栖热放线菌和变形斑沙雷氏菌腐败的菌株，尽管它生长不太好且未使产品酸化。嗜冷明串珠菌EU2247抑制了这2种SSO的生长并降低了pH值，但对感官品质没有影响。最后，在2种天然污染的产品中测试了鱼乳球菌，对其中一批产品有积极影响。这种影响与通过非培养和培养技术确定的微生物生态系统无关。基于这些结果，讨论了选择策略。
