延长初发酵培养时间对大肠菌群检测结果的影响

目的:为了解延长初发酵培养时间对各类样品大肠菌群检测结果的影响。方法:依据国标法检测大肠菌群数,将初发酵培养18～24 h未产酸产气的阴性管样品继续培养至36～48 h,对7类358份样品进行大肠菌群数的检测。结果:延长初发酵培养时间至36～48 h,另有68份迟缓发酵样品检出大肠菌群,大肠菌群检出率平均提高了19.0%,各类样品大肠菌群检出率分别提高了:酱卤肉9.8%、冷菜24.4%、果汁饮料40.7%、含奶冰冻饮品21.2%、食用冰块17.1%、桶装纯净水13.2%和表面涂抹样品6.4%。比较各类样品在18～24 h和36～48 h大肠菌群数的不合格率,果汁饮料有比较显著的差异(χ2=7.0,P<0.01)。结论:延长初发酵培养时间可不同程度提高样品的大肠菌群检出率,为某些样品大肠菌群测定的国标修订提供了实验依据。

延长初发酵培养时间对大肠菌群检测结果的影响

目的为了解延长初发酵培养时间对各类样品大肠菌群检测结果的影响。方法依据国标法检测大肠菌群,将初发酵培养18～24h未产酸产气的阴性管样品继续培养至36～48h,对7类358份样品进行大肠菌群的测定。结果延长初发酵培养时间至36～48h,另有68份迟缓发酵样品检出大肠菌群,大肠菌群检出率平均提高了19.0%,各类样品大肠菌群检出率分别提高了:酱卤肉9.8%、冷菜24.4%、果汁饮料40.7%、含奶冰冻饮品21.3%、食用冰块17.1%、桶装纯净水13.2%和表面涂抹样品6.5%。比较各类样品在18～24h和36～48h大肠菌群数的超标率,果汁饮料有比较显著差异(χ2=7.0,P<0.01)。结论延长初发酵培养时间可不同程度提高样品的大肠菌群检出率,为某些样品大肠菌群测定的国标修订提供了实验依据。

Study on the Monascus Pigment of Monascus Strains JF-02 Fermentation

[ Objective] The aim was to study the fermentation technology of monascus pigment of monascus strains JF-02. [ Method] Single factor experiment was carried out to study the influence of temperature, initial pH, culture time, different agricultural byproduct, and nitrogen source on monascus pigment in fermentation solution. Meanwhile, orthogonal experiment was conducted to get the optimal culture medium and cultivation condition. [ Resultl The optimal gene in the pigment of monascus pigment was 200 g/L of rice, 30 g/L of sweet potato powder, 10 g/L of glucose, 15 g/L of monosodium glutamate, 0.1% of zinc sulfate, and 0.1% of magnesium sulfate. The optimal culture condition was 30 ℃ and initial pH was 6.0. Fermentation time was 72 h, but when 24-L fermentation pot was used, culture time can last to 84 h. [ Condusion] The study provided theoretical basis for the development and application of monascus strains.