PDF(Pubmed)
Abstract：
Modified atmosphere packaging (MAP) is a common strategy to selectively prevent the growth of certain species of meat spoiling bacteria. This study aimed to determine the impact of high oxygen MAP (70% O2, 30% CO2, red and white meats) and oxygen-free MAP (70% N2, 30% CO2, also white meat and seafood) on preventing the growth of spoiling photobacteria on meat. Growth of Photobacterium carnosum and P. phosphoreum was monitored in a meat simulation media under different gas mixtures of nitrogen, oxygen, and carbon dioxide, and samples were taken during exponential growth for a comparative proteomic analysis. Growth under air atmosphere appears optimal, particularly for P. carnosum. Enhanced protein accumulation affected energy metabolism, respiration, oxygen consuming reactions, and lipid usage. However, all the other atmospheres show some degree of growth reduction. An increase in oxygen concentration leads to an increase in enzymes counteracting oxidative stress for both species and enhancement of heme utilization and iron-sulfur cluster assembly proteins for P. phosphoreum. Absence of oxygen appears to switch the metabolism toward fermentative pathways where either ribose (P. phosphoreum) or glycogen (P. carnosum) appear to be the preferred substrates. Additionally, it promotes the use of alternative electron donors/acceptors, mainly formate and nitrate/nitrite. Stress response is manifested as an enhanced accumulation of enzymes that is able to produce ammonia (e.g., carbonic anhydrase, hydroxylamine reductase) and regulate osmotic stress. Our results suggest that photobacteria do not sense the environmental levels of carbon dioxide, but rather adapt to their own anaerobic metabolism. The regulation in presence of carbon dioxide is limited and strain-specific under anaerobic conditions. However, when oxygen at air-like concentration (21%) is present together with carbon dioxide (30%), the oxidative stress appears enhanced compared to air conditions (very low carbon dioxide), as explained if both gases have a synergistic effect. This is further supported by the increase in oxygen concentration in the presence of carbon dioxide. The atmosphere is able to fully inhibit P. carnosum, heavily reduce P. phosphoreum growth in vitro, and trigger diversification of energy production with higher energetic cost, highlighting the importance of concomitant bacteria for their growth on raw meat under said atmosphere.
摘要：
气调包装（MAP）是选择性防止某些肉类腐败细菌生长的常用策略。这项研究旨在确定高氧MAP（70％O2，30％CO2，红色和白色肉类）和无氧MAP（70％N2，30％CO2，还有白肉和海鲜）对防止细菌生长的影响。在不同的氮气混合物下，在肉类模拟培养基中监测了肉生细菌和磷菌的生长。氧气,还有二氧化碳,并且在指数生长期间采集样品用于比较蛋白质组学分析。大气下的生长似乎是最佳的，特别是对于P.carnosum。增强的蛋白质积累影响能量代谢，呼吸,耗氧反应，和脂质的使用。然而,所有其他大气都显示出一定程度的增长下降。氧浓度的增加导致抵消两种物种的氧化应激的酶的增加，并增强血红素利用和磷酸磷的铁硫簇组装蛋白。缺乏氧气似乎将代谢转向发酵途径，其中核糖(P.磷酸)或糖原(P.carnosum）似乎是首选的底物。此外,它促进了替代电子供体/受体的使用，主要是甲酸盐和硝酸盐/亚硝酸盐。应激反应表现为能够产生氨的酶的积累增强(例如，碳酸酐酶,羟胺还原酶）并调节渗透胁迫。我们的结果表明，光细菌无法感知二氧化碳的环境水平，而是适应自己的无氧代谢。在厌氧条件下,在二氧化碳存在下的调节是有限的并且是菌株特异性的。然而,当类似空气浓度的氧气（21％）与二氧化碳（30％）一起存在时，与空气条件（非常低的二氧化碳）相比，氧化应激似乎增强了，如解释两种气体是否具有协同作用。在二氧化碳存在下氧气浓度的增加进一步支持了这一点。大气能够完全抑制肉鱼，在体外大量减少磷酸假单胞菌的生长，并以更高的能量成本引发能源生产的多样化，强调伴随细菌对其在所述气氛下在生肉上生长的重要性。
