Study on the Tolerance of Three Pathogens to Temperature and pH Value on'Dongzao'Jujube Fruit

The tolerance of three pathogens (Pseudomonas sp.,Xanthomonas sp. and Erwinia sp.) to temperature and pH value was studied. The pathogens could induce 'Dongzao' jujube fruit decay. The results showed that the tolerance of Pseudomonas sp. to low and high temperature was 0 ℃ and 57.5 ℃, Xanthomonas sp.'s was -2 ℃ and 55 ℃, Erwinia sp.'s was 0 ℃ and 57.5 ℃. The tolerance of the three pathogens to alkalescence was more resistant, Pseudomonas sp. could not growth until pH value was 10, Xanthomonas sp. and Erwinia sp. could still growth normally when pH value was 12; at the range of acidity, when pH value was 2～4, the growth of three pathogens were inhibited. In the combination test of pH, temperature and time, when pH value range was 3～4, the treatment time was 6～8 min, the temperatures of Pseudomonas sp.,Xanthomonas sp. and Erwinia sp. were 45 ℃, 55 ℃ and 50 ℃ respectively, their growth were inhabited obviously.