肉制品中亚硝酸盐测定能力验证

为加强肉制品安全监督管理，进一步提升检验检测机构对肉制品中亚硝酸盐含量的检测能力，确保提供的检测数据准确、可靠，组织实施肉制品中亚硝酸盐含量检测能力验证计划。制备含亚硝酸钠的鸡肉火腿肠，向42家实验室随机发放样品，在规定时间内回收检测数据。对检测结果进行稳健统计分析，以Z值评价各个实验室的检测能力，并对非满意结果的实验室通过查阅原始记录进行技术分析。结果表明：制备的能力验证样品均匀、稳定，满足能力验证计划要求；42家实验室总体结果满意率为81.0%，表明实验室对肉制品中亚硝酸盐含量的检测能力较好；部分实验室发现检测过程中所存在的问题，并加以改正，使自身检测能力进一步提高。

Isolation,Identification and Spoilage Ability of Dominant Spoilage Bacteria from Channel Catfish

This study was conducted in order to investigate the specific spoilage organisms (SSOs) in cold stored channel catfish and their spoilage ability. Eight strains of spoilage bacteria were isolated and identified from channel catfish at the end of refrigerated storage by traditional selective culture combined with 16S rDNA sequence analysis. Based on the sensory score of channel catfish inoculated with each of the spoilage strains after 0–8 days of storage, four strains of SSOs were selected for identification by their colony and morphology characteristics, physiological and biochemical properties and 16S rDNA sequence. The strains were inoculated into sterile fish fillets and stored at 4 ℃ for up to eight days. The total number of colonies and total volatile basic nitrogen (TVB-N) content were determined during the storage period. The yield factor of spoilage bacteria metabolites (YTVB-N) was used as an indicator to measure the spoilage ability of spoilage bacteria. The results showed that the SSOs in channel catfish were two strains of Shewanella putrefaciens, Pseudomonas aeruginosa and Pseudomonas aeruginosa. All the four strains could cause spoilage of sterile fish fillets, with Shewanella having the strongest spoilage ability.