15D-8 |
Controlling Alicyclobacillus acidoterrestris spores with chlorine dioxide on laboratory medium and apples |
P. M. Gray, D. H. KANG, and R. H. Dougherty. Department of Food Science and Human Nutrition, Washington State University, PO Box 646376, Pullman, WA 99164-6376 Alicyclobacillus acidoterrestris is an important spoilage organism of apple juice. This acid-tolerant, spore-forming bacterium resists conventional pasteurization. One of the A. acidoterrestris contamination sources is the apple itself. Therefore control of A. acidoterrestris spores on apples, prior to juicing, is necessary for preventing apple juice spoilage. The purpose of this study is the application of a chlorine dioxide to reduce the numbers of A. acidoterrestris spores on laboratory media and apples. Forty ppm free chlorine dioxide reduced the numbers of A. acidoterrestris spores in laboratory media by 0.1, 0.7, and 4.4 log10 for 0.5, 1, and 5 min treatments, respectively. Eighty ppm free chlorine dioxide reduced populations by 1.0, 2.8, and >5.4 log10 for 0.5, 1, and 5 min treatments, respectively. One hundred twenty ppm free chlorine dioxide reduced numbers by 2.10, 4.8 and >5.4 log10 for 0.5, 1, and 5 min treatments, respectively. For 4 different cultivars of apples (Red Delicious, Golden Delicious, Gala, and Fuji), 40 ppm free chlorine dioxide reduced A. acidoterrestris spore numbers by 1.5, 3.2, 4.5, >4.8 log10 after 1, 2, 3, and 4 min treatments, respectively. One hundred twenty ppm free chlorine dioxide reduced spore numbers by >4.8 log10 after only 1 min treatment. These results show the great effectiveness of chlorine dioxide in controlling A. acidoterrestris spores on apples. This information will be useful to food processors wanting to prevent A. acidoterrestris spoilage of apple juice.
Session 15D, Food Microbiology: Fruits and vegetables
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