Studies On Prevention And Cure The Contaminative Bacterium Of Yeast In Beer

This text analyzes the beer ferments sanitary advance in craft and existentproblems of Jiangxi Jindezheng Brewery Co., Ltd after the system technique has beenreformed. After analyzeing, made sure thatyeast were one of contaminative sources.A series of the research proceeded for this and conclusions got as follows:1. In order to prevention and Cure the headstream of yeast contaminated bybacterium and wilding yeast,in order to settle the question of yeast degradation andvariation, in order to keep the pureness of yeast, refer to original data of yeast,separating and filtrating yeast regularly can keep the character of original yeaststrain, can stabilize quality and flavor of beer.2. According to contaminated condition in beer, the reclaimed yeast sediment,added by acidize super saturation ammonium sulfate, a great lot of yeast dead, theraise value of yeast death rate even reach 10%, and that does not effect to anaerobicbacteria; 99% bacteria can be killed with adding 50ppm acidized Nisin into yeastsediment; only phosphoric acid be added into yeast, and some arts and craft becontrolled like pH 2.5, action time 2 hr, superadd acid at 30 min, can kill over 99.9%bacteria within the raise value will be accepted.3. Fix quantify ration addition device is adopted of yeast sediment acidificationmanage system in big production, adding phosphoric acid slowly and equably into thepipeline through which yeast enter into tank, controlling pH 2.4-2.8, action time 2hours, yeast sediment is mixed equably with phosphoric acid solution, the raise valueof yeast death rate is rather lowly, the average is 1.55%, the average of killed rate ofaerobic bacteria is over 98.0% and the average of killed rate of anaerobic bacteria isover 99.9%; the act intension of phosphoric acid does rather effect to the killed rate ofanaerobic bacteria, in despite of lab or big production, all the killed rates of bacteriaare over 99.9% when pH is controlled under 2.5, the anticipate aim will attain.4. According to contaminated condition in clear beer, the extensiveness andefficiency of restrain bacterium of Nipagin complex esters can restrain familiarcontaminated microorganism and yeast, especially can restrain yeast and lactobacilluswhose MIC is 12 mg/L, can restrain coliform bacteria and obesumbacterium proteusless than former Nipagin complex esters still have the ability of restraining bacillusafter the condition of 121℃in 30 minutes, that explain the better stabilizationability after heated. Nipagin complex esters still can keep the ability of restrainingbacillus to pasteurization. Nipagin complex esters have the certain application prospect in the beer production. Being added in filtrated beer Nipagin complex esterscan pasteurize contaminated bacterium and yeast, without pasteurization or suitablyreduces the sterilization intensity.