Elimination of Listeria monocytogenes contaminated on vegetables by chlorine dioxide
2002
Nattawut Maskran(Kasetsart University. Bangkhen Campus, Bangkok (Thailand). Faculty of Agro-Industry. Department of Food Science Technology) | Warapa Mahakarnjanakul(Kasetsart University. Bangkhen Campus, Bangkok (Thailand). Faculty of Agro-Industry. Department of Food Science Technology) | Tanaboon Sajjaanantakul(Kasetsart University. Bangkhen Campus, Bangkok (Thailand). Faculty of Agro-Industry. Department of Food Science Technology)
Concerning of nutrition value of fresh produce urged consumers increase consumption of the products. However inappropriate washing step cannot eliminate foodborne pathogens contaminated on produce, consequently in many western countries it becomes the cause seriously outbreaks. Soaking and washing lettuce, that artificially contaminated with Listeria monocytogenes 3.6 log 10 CFU/mL, in chlorine dioxide solution concentration of 3, 4, 5, 6 and 10 ppm at 30 (+-2 deg C) for 10 min could completely eliminate the bacteria. While soaking and washing lettuce at lower contamination of 2.6 log 10 CFU/mL at concentration of 3 ppm only 5 min could destroy all cells. At the same condition total microorganisms were reduced to 2.2 log 10 CFU/mL (or 99.4 percent). Similarly body corn contaminated at 3.4 and 2.4 log 10 CFU/mL were conducted. At concentration of 3, 4, 5, 6 and 10 ppm could completely eliminate L. monocytogenes cells and reduced total microorganisms by 1.9 log 10 CFU/mL (or 98.9 percent) in baby corn. However, at high concentration of 10 ppm caused strong smell and off-flavor in both vegetables. Using chlorine dioxide solution at concentration of 3 and 5 ppm for soaking and washing natural contaminated lettuce were done. Washed lettuce were dept in different temperature at 30(+-2) deg C, 4(+-1) deg C and 10(+-1) deg C. Results showed that the total aerobic count were not significantly different from washing lettuce with tap water. Population decreased about 1-1.8 log 10 CFU/mL since the chlorine dioxide solution could not eliminate all spoilage bacteria. It could be concluded that using chlorine dioxide solution at the appropriate conditions for washing and soaking produce obviously destroy foodborne pathogen and increase wholesomeness for consumption.
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