Screening Of Bacteria Strains To Be Used In Fermented Sausage And Study On Mechanism Of Action

In this research strains such as lactic acid bacteria, Micrococcus, StapHylococcus were isolated and screened from fermented meat product. After capacity of acid and growth were tested, 4 strains with excellent characteristics were selected and preliminary identified. As starter the strains were applied to fermented sausage and their mechanism of action were discussed. The report including several parts as follows:1.67 stains of Gram-positive and 58 stains of Gram-positive cocci were isolated from fermented sausage, Chinese sausage and ham with MRS agar and MSA agar. Based on the standards of screening lactic acid bacteria, Micrococcus and StapHylococcus for fermented meat product, four stains of lactic acid bacteria including RFx1,RH33,RF261 and RL32 and four stains of Gram-positive cocci such as AFx5,AHx1,AF5b and ALx3 were screened. The four stains of lactic acid bacteria did not produce CO₂ from glucose,H₂S,NH₃ from arginine,H₂O₂ and slime. They also had no decarboxylase activity and they can resist nitrite and Nacl.Acidificaction rate and acidifying capacity of them were better than others.E.coli and S.aureus were inhibited by them. AFx5, AHx1, AF5b and ALx3 displayed nitrate reduction, catalase-positive, proteinase and lipase activity beyond some characteristic of RFx1, RH33,RF261 and RL32.2.After growth capacity of all strains and acidifying capacity of lactic acid bacteria were tested at different temperature, I knowed that the growth and acidifying capacity of RFx1 and RF261 were better than RH33 and RL32 at low temperature (10℃). The growth capacity of AFx5 and ALx3 were better than AHxl and AF5b at the same temperature.The growth of RFx1 and RF261 had inhibition to AFx5 and ALx3 to a degree in mixed cultivation and the inhibition of RFx1 was stronger than RF261 during ferment propHase, but AFx5 and ALx3 could breed a lot in general. RFxl, RF261, AFx5 and ALx3 were selected to identify.3.Based on pHenotype and pHysiological biochemical characteristic RFx1 and RF261 were preliminary identified as L.delbruecki, AFx5 and ALx3 were preliminary identified as M.varians and S.carnosus.4. According to acute toxicity test, AFx5 and ALx3 are safety.5.Fermented sausage was produced with the selected strains and their mechanism of action was disscussed after changes of microbial succession, pHysico-chemical properties, biochemistry properties and sensory quality were studied. The lactic acid bacteria was also dominant flora in without addition group, its maximum bacterial number was 10^8-9cfu/g and pH was lower than 5.0 at the eighth day. Aw was accecelerated decrease and sensory quality such as hardess, gumminess, springiness and flavor were improved with fermented action of microorganism. On the other hand, decompound of nitrite was promoted faintly with the fermented action of microorganism. The growth of lactic acid bacteria can expedite death of enterobacteriaceae .The catalase that M.varians and S.carnosus produced can prevent the oxidation of lipid significantly and the multiplication of M.varians and S.carnosus can improve colour significantly. Relatively speaking, entogenous enzyme is more important to...