芹菜贮藏过程中亚硝酸含量与微生物动态关系研究

Dynamic relationship between nitrite content and microorganisms in celery during storage

目的:分析不同初加工方式和贮藏温度下芹菜中亚硝酸盐含量和菌落总数,研究亚硝酸盐含量与微生物之间的动态关系。方法:检测芹菜在保持原状、颗粒状、粉末状3种初加工方式和1、4、8℃3种贮藏温度下亚硝酸盐含量和菌落总数,分析高亚硝酸盐样品中代表性菌株的硝酸盐还原特性。结果:(1)芹菜在8℃下贮藏时最早检出亚硝酸盐,且亚硝酸盐积累量最大;(2)粉末状芹菜最早检测到亚硝酸盐,亚硝酸盐最大积累量为240 mg/kg(以N计);(3)菌落总数达到107 cfu/g亚硝酸盐开始检出,菌落总数达到108 cfu/g时芹菜中亚硝酸盐含量达到峰值;(4)菌株分析发现6株细菌具有硝酸盐还原特性,为挑取总菌落数的6/10。结论:芹菜中菌落总数变化与亚硝酸含量变化存在动态关系,初步推断硝酸盐还原菌大量繁殖导致了芹菜中亚硝酸盐的积聚。

Objective： The paper detected the change of nitrite content and total plate count by different primary processed methods in celery stored in different temperatures, and explored the dynamic relationship between two. Methods： Celery was pretreated as stay the same, granule, powder and then stored at 1 ℃, 4 ℃ and 8 ℃. The nitrite content and total plate count were detected by reagent strip and plate count method. The typical strains which showed nitrate reduction capability were confirmed in high nitrate sample. Result：（1） If the storage temperature was 8 ℃, the nitrite was detected initially and the maximum accumulation was obtained.（2） Celery powder detected nitrite firstly and the maximum accumulation was 240 mg/kg（by N count）.（3）Nitrite was detected in samples if colony numbers reached 107 cfu/g, the peak value of nitrite appeared when colony numbers were 108 cfu/g.（4） 6 trains showed the ability to reduce nitrate, accounted for 6/10 of all candidate strains. Conclusion： The nitrite content and total number of colonies in celery had dynamic relationship. Reproduction of bacteria which had the capability of nitrate reduced caused accumulation of nitrite in celery.