Screening And Qualification Of The Fermented Sausage Strain And Effect Of Environment Factors On Microorganism During Fermentation

Purification of the strains from fermented meat were screened and identified, and a screening system was created to select suitable mixed of fermented meat starter cultures, a culture medium for cell multiplication of Lactic acid bacteria (Lactobacillus plantarum) was optimized by using the SAS9.0 software. During the ripening process Microbiological changes, changes in product quality characteristics and the physico-chemical properties forming, and the relationship between the environment factors and various microorganisms using response surface methodology was studied. The results included several parts as follows:1,2 strains(RFx1,RB3)with excellent characteristics were selected according to the fermentation and growth capability on the basis of fermented dry sausage. RFx1 was Lactobacillus delbrueck, RB3 was Lactobacillus plantarum through identification.2,The optimal concentration of multiplication of twelve promotion the sucrose,the whey powder, the beer and the initial pH of the media were screened as the main effect factors from 13 factors including the initial pH of the media and 12 promotion factors by using a Plackett-Burman design. Last, the central composite design and the response surface analysis were used to determine the optimal levels of the promotion factors and the initial pH of the media. The optimized conditions were:MRS supplemented with 7.42g/L whey powder, 64.8ml/L beer juice and 4.30g/L sucrose, the initial pH of the media was 6.25.In this condition, the concentration of L-RB3 was increased from 2.8×108cfu/ml to 1.43×109 cfu/ml, which was as 5 times as that using the quondam media.3,Lactic acid bacteria (LAB) are the predominant microflora during ripening of fermented sausages. They rapidly maximized with population of 108cfu/ml in 7 days in the four type products respectively, and stayed almost constant afterwards. During the ripening days, they decreased. Micrococci-staphylococci were the same to LAB all the time in the process of fermented dry sausages. In the first three days of fermentation, the pH dropped rapidly to below 5.0. Afterwards, a slight increase in pH was observed seven days later. There was almost no change in moisture content during fermentation. Starter culture has some influence on the content of total nitrogen and free amino acid.4,The sausage treated with starter showed significantly higher values for hardness, gumminess, and chewiness as compared to other treatments. Red value of sausages was increased significantly in case of samples inoculated with Micrococcus varians and Staphylococci carnosus. From the sensory evaluation results, both of starter culture sensory attributes such as appearance, color, flavor and overall improved the acceptability of products.5,Effect of environment factors, such as salt concentration, water activity, temperature and time of fermentation, sugar concentration etc. on total bacteria, lactic acid bacteria and microcococcus was studied with response surface experiment design. Significant environmental factors were assured and scientific mathematical models were founded. Conditions of the best technology of traditional fermented sausage were salt 5%, Aw 0.95, fermentation temperature 14℃, fermentation time 20d, and sugar 2%. Applied the mathematical model to predict the number of microorganism during fermentation, the result was credible. It gave some information to regulate fermentation, provide safety of fermented sausage products and shorten production cycle, and also provide important scientific bases for prediction microbiology.