| Alicyclobacillus acidoterrestris, also called as thermophic acidophlic bacteria(TAB), is an important target micro-organism in quality control of apple juice concentrate(AJC). The spores of A. acidoterrestris are relatively heat resistant and can surive conventional pasteurisation treatment, and they can germinate and outgrow under suitable conditions causing spoilage juice. There are always demands for A. acidoterrestris being less than 1cfu/10g AJC in international trade of AJC. The D value of A. acidoterrestris's spore is 23min, which makes it challenges traditional thermal sterilization methods. To date, there is no feasible ways to control it. After China' entry to WTO, import country give our AJC more and more rigorous demands. A. acidoterrestris is one of the most serious quality problems in China AJC industry.Ozone is formed by the rearrangement of oxygen molecules. It is a bluish gas with pungent odor and oxidizing properties. Ozone is active against all forms of microorganisms at relatively low concentrations and in very short time, which makes it one of the most popular sanitizers known. Ozone can auto-decompose rapidly to produce oxygen, thus it leaves no residues .The rapid development of ozone application is a clear indication of the efficacy and usefulness of ozone. Food and Drug Adiministration(FDA) has already approved of ozone as a direct food additive for the treatment ,storage, and processing of foods. Although it is widely used in above aspects, ozone hasn't been used in the production of apple juice concentrate (AJC). In order to introduce ozone to AJC and explore it's feasible use as a sanitizer to A. acidoterrestris, The lethal effect to A. acidoterrestris is studied for providing some relevant information about non-thermal sterilization.In this paper, three main contents were studied. First, the solution properties of ozone in water and it's attenuation pattern. Ozone gas was bubbled into water contained in a filler with sandstone. Concentration of ozone was measured with iodine stoichiometry titration method. Secondly , the lethal effect of ozone to A. acidoterrestris in water. A. acidoterrestris were got from apple juice concentrate produced by shaanxi hengxi fruit juice company. According to the procession and requirement in 《technological Specification of Experiment on Disinfection and Sterilization》, sterilizing tests by using blowing ozone water and ozonized water on suspended matter of A. acidoterrestris were conducted. The lethal effect of this two sterilizing methods is compared. Thirdly, sterilizing effect of ozone toA.acidoterrestrison surface of glass and apple. Through the single factor experiment, including pH value, temperature, killing time, and blowing ozone time, the orthagonal experiment of L9(34) was conducted. By the experiment of, the best lethal condition of ozone to A. acidoterrestris were ascertained.Through studies, the conclusion are as follows:(1) he effects of temperature ,pH value ,and water quality on the solution of ozone in water were studied.The experimental results showed that lower temperature, lower pH value (especially being four) and high pure water were vail to the solution of ozone in water. Adding ozone blowing time could get high concentration ozone water.(2) The stability of ozone water was nearly related to temperature. Half life of ozone water was 34min when temperature was 15C; it was 23min when temperature was 25C and 18min as temperature reached to 35C.(3) Suspension quantitative germicidal test indicated that the ozone water whose concertration was 31.1mg/L could kill 99.14% of A. acidoterrestris in 5 minites.(4) Studies showed that sterilizing effects were better by using blowing ozone water than ozonized water. Sterilizing rate reached to 99.18% when we Wowed ozone to A. acidoterrestris's suspension 5 minites.(5) The lethal effect of ozone to A. acidoterrestris was affected by blowing time , temperature, pH value and sterilizing time. And the result of experiment indicated that blowing time was mai...
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