The Studies On Preparation Of High Efficiency And Concentrated Starter Specialized For The Low Temperature And Low Acid Fermented Beef Products

Biotechnological characteristics, high density cultivation, combined cryoprotectants of concentrated cultures production and quality guarantee-time of starts cultures.et al. were studied here systemically with three strains including Lactobacillus plantarum, Pediococcus pentosaceus and Staphylococcus xylosus, which were separated and identified from naturally fermented dried beef-Bundnerfleisch. The results were following:The result of the fermenting characteristics of the strains indicated that three strains have the properties to endure high salt and high nitrite;Lactobacillu plantarum and Pediococcus pentosaceus could affect the decomposition of protein, Staphylococcus xylosus could affect the decomposition of protein and fat;Lactobacillus plantarum and Pediococcus pentosaceus could inhibit the growths of some pathogenic bacteria, but Staphylococcus xylosus couldn't.The optimum mediums of these three bacteria were obtained. The optimum medium of Lactobacillus plantarum was based on the malt juice medium adding with 0.5% lactose, 1% peotone beef, 5% yeast extract,5% tomato juice;the optimum medium of Pediococcus pentosaceus was based on the malt juice medium adding with 0.5% lactose, 1.5% peotone beef, 5% yeast extract, 10% tomato juice;the optimum medium of Staphylococcus xylosus was based on the malt juice medium adding with 0.5% glocuse, 1.5% peotone beef, 0.1 %beef extract, 1 %sodium chloride.This paper studied the culture conditions of Lactobacillus plantarum, Pediococcus pentosaceus and Staphylococcus xylosus.The culture conditions of Lactobacillus plantarum and Pediococcrs pentosaceus were: cultured temperature 20℃, initial pH value 6.5~7.0, cultured time 20h;the culture condition of Staphylococcus xylosus was: cultured temperature 20℃, initial pH value 7.0, cultured time 20h. After incubation, the viable counts of three strains were 3.75×10~9cfu/mL, 3.68×10~9cfu/mLand 5.00×10~9cfu/mL.The concentrating enrichment conditions were studied and chosen, the results illstruted that the centrifugal effect was better than the bacteria filter;the effect of high rpm was helpful for bacteria's concentrating, improved the centrifugation concentrating times.The results indicated that the best effect could be obtained at 0~4℃ with 6 000rpm for 30min.Using 12% skimmed milk as suspended substrat, the function of protectors includingsucrose, glycerin was studied. Results suggested that sucrose, Vc, glycerin and CaCO3 had better effects on promoting cell count. According to orthogonal experiment, the optimal combined cryoprotectants of Lactobacillus plantarum, Pediococcus pentosaceus and Staphylococcus xylosus contained the following ingredients were based on the modified skimmed milk adding with 5% lactose, l%Vc, 5%glycerin and 3%CaCC>3;based on the modified skimmed milk adding with 4% lactose, l%Vc, 3%glycerin and 2%CaCC>3;based on the modified skimmed milk adding with 3%lactose, 1.5%Vc, 5%glycerin and 2%CaCO3. The survival of Lactobacillus plantarum, Pediococcus pentosaceus, Staphylococcus xylosus got to 63.01%, 66.20% and 70.47%;the cell suspension in freeze-drying culture starter containing the suitable protector might be lyophilized into the strains with high viability(the number of viable cell 2.62xl010cfu/g, 2.54x1010cfu/g and2.91xl010cfu/g).Measuring of quality guarantee-time: Storage effect under freezing condition and refrigeration condition was superior to those under indoor temperature, but the contrast was smallness.The prepared solid fermentation agents are stored under refrigeration condition for six months.