气调包装淡水鱼微生物菌群的演替及其对顶空气体变化的响应

Modified atmosphere packaging (MAP) has become an increasing popular preservation technique, bringing major changes in storage of raw products to meet consumer demands for fresh, healthy and safe foods, showing positive effect on shelf-life in cold chain. In order to overcome the setback of most existing MAP design, which has been mainly empirical with “trial and error” or “pack and pray” approach, an improved understanding of dynamic changes of headspace gas were considered to be the base for MAP design. The microbial succession in MAP aquatic product during storage and response of microflora to the headspace gas change should be monitored. In our preliminary research, specific spoilage organism (SSO) had been identified with fingerprinting molecular method (16S rDNA-RFLP) in crisped grass carp with different package during storage. It has been suggested that identification of the dominant microflora in different stage of storage was essential for developing the new technology of target inhibition on microorganism. Based on these, we select grass carp （one of most abundant freshwater fish species in China） and crisp grass carp (one of freshwater fish with special texture, cultivating in south of China) as our research subjects. The headspace gas profile in MAP fish during storage in cold chain would be plotted and mass transfer between headspace gas and fish would be modeled basing on artificial neural network (ANN). Pronounced change of microflora coincided with the change in gas profile. The succession of microflora diversity of fish in MAP during storage would be plotted by combination of polymerase chain reaction (PCR) based molecular technology-denaturing gradient gel electrophoresis (DGGE) and conventional evaluation of spoilage characteristic including physicochemical index and sensory index. Dominant microbial of different stage would be identified by high throughput sequencing technology. The spoilage potential of dominant microbial would be evaluated by inoculation into sterile raw fish followed by storage in MAP model system and the effect of their interaction were evaluated by co-culture in MAP model system. The growth curve and interaction would be modeled by applying Baranyi model, Square root model and the modified Lotka-Volterra model. Based on the interaction among microflora and the microbial succession in MAP during storage, the response of microflora to MAP would be analysis comprehensively. This study would give the significant improvement for MAP design and MAP optimization and provide the theory foundation for developing multi-target hurdle technologies.

气调包装（MAP）因能延长食品货架期且安全卫生成为最有潜力的保鲜手段之一，而确定微生物菌群在保鲜过程中的演替进程及其对环境变化的响应模式是设计和优化MAP方案的基础。本项目在确定不同包装脆肉鲩SSO的基础上，以大宗淡水鱼（鲩鱼）和特色淡水鱼（脆肉鲩）为研究材料，绘制鱼肉在MAP环境中顶空气体的变化图谱，同时建立基于ANN的气体与鱼肉样品传质模型；应用PCR-DGGE监测微生物菌群的演替规律，进而结合高通量测序识别不同阶段的优势菌；比较优势菌在纯培养、单独接种及混合接种于模拟MAP环境中的生长特性及腐败特性，探讨气体环境对微生物的影响及菌群的相互作用；结合Baranyi、平方根方程及改良Lotka-Volterra构建优势菌的生长及交互作用模型，确定微生物菌群对MAP环境的响应模式。该项目可为阐明MAP原理提供基础资料，避免MAP在方案设计及优化方面的盲目性；同时为开发靶向抑菌奠定理论基础。