Increasing the efficiency of sodium hypochlorite in the reduction of Salmonella typhimurium
1998
Rungtiwa Isarangporn
Poultry and shrimp products were contaminated by Salmonella. The effects of sodium hypochlorite on the reduction of Salmonella typhimurium were studied. The pure culture 10*[2) CFU/ml of S. typhimurium was killed at 10 and 1 min in 50 and 100 ppm of sodium hypochlorite at pH range 9-11 which had available chlorine 16.13 and 29.77 ppm, respectively. When increased the pure culture to 10*[3) CFU/ml at sodium hypochlorite 100 ppm the destruction time was within 2 min. The efficiency of sodium hypochlorite was improved to obtain pH 7.0 by using potassium hydrogen phosphate buffer. The pure culture of S. typhimurium at 10*[2) CFU/ml was killed at 20, 2 min and 30 sec in 10, 20 and 30 ppm which had available chlorine CFU/ml was killed at 20, 2 min and 30 sec in 10, 20 and 30 ppm. Which had available chlorine 4.25, 6.38 an 9.92 ppm, respectively . Increasing of the pure culture to 10*[3) CFU/mL at sodium hypochlorite 20 and 30 ppm. S. typhimurium was killed at 4 and 1 min. The injured cells of S. typhimurium increased to 100 percent at 3 min, 30 and 15 sec by using sodium hypochlorite 10, 20 and 30 ppm for initial cells 10*[2) CFU/ml and at 10 min and 45 sec by using the same chemical substance at concentration of 20 and 30 ppm, respectively for initial cells 10*[3) CFU/ml. In comparison with the effect of sodium hypochlorite 10, 30 and 50 ppm with various concentration of citric acid adjusted to pH 4.0 and 7.0 by sodium hypochlorite 10 ppm and citric acid 0.03 M with sodium hypochlorite 30 and 50 ppm reduced both pure culture at 10*[2) and 10*[3) CFU/ml. Using sodium hypochlorite 10, 30 and 50 ppm with sodium citrate and citric acid 0.1 M at the same pH and temperature found that the destruction time of pure culture at 10*[3) CFU/ml was 2, 1 min and 30 sec, respectively.
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