酸菜中降解亚硝酸盐乳酸菌的筛选、鉴定及其在发酵香肠中的应用

目的:依据多项评价指标筛选亚硝酸盐降解能力强且适用于肉制品发酵的乳酸菌。方法:首先采用添加0.3%Ca CO3的MRS培养基从15份不同产地的农家自制酸菜中筛选乳酸菌,其后以降解亚硝酸盐能力和肉制品发酵剂所需要求为筛选指标对初筛所得乳酸菌进行复筛,并对其进行菌种的分子鉴定。最后以筛选到的菌株为发酵剂制作单菌株发酵香肠,通过检测香肠在发酵和贮藏期间的Na NO2含量来进一步验证所得菌株的实际降解亚硝酸盐能力。结果:筛选到1株降解亚硝酸盐能力优良(降解率为78.77%)且适于肉制品发酵的乳酸菌菌株,16S r DNA全序列分析鉴定为鼠李糖乳杆菌(Lactobacillus rhamnosus GG,ATCC 53103)。香肠发酵实验结果显示,在发酵结束时香肠的Na NO2含量为12.2 mg/kg,低于国家标准。同时,微生物指标检测结果证明了此条件下生产的发酵香肠的质量是安全可靠的。结论:鼠李糖乳杆菌能有效降低发酵香肠中的Na NO2含量,可用于开发成用于生产低亚硝酸盐的健康、安全的肉品发酵剂。 

Isolation and identification of nitrite- degrading lactic acid bacteria from pickles and application in fermented sausage

Objective: To screen lactic acid bacteria from pickles,which could decompose nitrite in sausage.Methods: At first,lactic acid bacteria were screened from 15 different regional pickles,using MRS medium which add 0.3% Ca CO3. Secondly,further experiments were executed according to nitrate degradation efficiency and standards of meat starter,and the bacterial strain which acquired from experiment was identified by using 16 S rRNA encoding gene( 16 S r DNA) sequence.At last,fermented sausages were produced using the lactic acid bacteria asa starter,and concentrations of Na NO2 in fermentation and storage period were detected.Results: One strain of lactic acid bacteria meetsthe standards,and it was identified to be 100% similar to Lactobacillus rhamnosus GG.The nitrite concentration in fermented sausage was 12.2 mg / kg. At the same time,the results of microbiological detection demonstrated that with this condition,quality of the fermented sausage was safe.Conclusion: Lactobacillus rhamnosus GG could significantly eliminate the nitrite in fermented sausage,and could be used as an efficient and healthy starter in fermented sausage production.