89A-33 |
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W. KLAYPRADIT, P. Chhabra, and Y.-W. Huang. Dept. of Food Science & Technology, Univ. of Georgia, Food Science Bldg., Athens, GA 30602-7610 Chitosan, a modified carbohydrate polymer derived from chitin, has been of interest in the past few decades due to its potential broad range of food industrial applications. Our objective was to use chitosan to determine the growth inhibition effect on Salmonella spp. as tested in nutrient broth and in natural oysters. Three levels of chitosan, 1, 2, and 3 %, were prepared in 0.5 % acetic acid and the pH was adjusted to 6.5. Pure culture of Salmonella was inoculated into nutrient broth (control), nutrient broth containing 0.5 % acetic acid, and three levels of chitosan solution. All cultures were kept at 7o C for a period of 48 hrs. Inoculated nutrient broths were consecutively removed for plate count at a 12-hr interval for a period of 48 hr. Our results showed that the initial counts of all samples were averaged to 6.0 x 108CFU/ml. Seven-log reduction was observed after 48 hrs incubation at 7o C for all 3 levels of chitosan. However, 0.5% acetic acid alone showed only a 2 to 3 log reduction. Similar experiment was carried out on raw oysters with some modifications. Oysters were coated with chitosan concentrations 0, 0.5, 1, and 2% dissolved in 0.5 % hydrochloric acid solution, and then inoculated with Salmonella culture. Uncoated oysters were served as the control. Oysters were stored at 4 o C for 15 d. and checked for the growth of Salmonella at a 5–d. interval. The initial counts were averaged to 7.4 log CFU/ml. Overall results showed that 1% chitosan completely inhibited the growth of Salmonella by d. 15, thus acting most suitably in prevention of Salmonellaon raw oysters. These results suggest that 1% chitosan may be used as antibacterial agent to ensure the safe of food.
Session 89A, Aquatic Food Products: General
2005 IFT Annual Meeting, July 15-20 - New Orleans, Louisiana |