Microbiological Quality of Bean Sprouts and Other Vegetables Disinfected by Various Means

Enhancement of the Microbiological Quality of Selected Ready-to-EatVegetables Disinfected by Chloramine, Chlorine, Ethanol, and Ozone

2002FDA Science Forum

FDA:Building a Multidisciplinary Foundation

February20-21, 2002

WashingtonConvention Center, Washington, DC

PosterAbstracts, Board L-11

T. T. Tran, J. I. Uwaleke, R. L. Thunberg, C. R. Warner, andS. J. Chirtel. U.S. Food and Drug Administration, Washington, D.C. 20204.

The effect of chloramine (80ppm), chlorine (200 and 2000ppm), ethanol (10%), and ozone (2ppm) on the aerobic spoilage bacteria ofbroccoli, celery, lettuce, mung bean sprouts, parsley, and scallions wasinvestigated. Test portions (25 g) were treated with aqueous solutions of thesedisinfectants, and then analyzed for aerobic plate counts (APC). Theeffectiveness of different sanitation regimens was estimated by the difference(D) between the APC (in log10 cfu/g) of controls (C) and treatedportions (logD). The mean C values ranged from 5.5 to 9 log10 cfu/g.The overall effectiveness of ozone, chloramine, chlorine 200 and 2000 ppm, andethanol were 0.2, 0.5, 1.2, 1.9, and 1.7 logD, respectively. Significantdifferences (p<0.05) in counts (logD) were seen in 1 out of 5, 4 of 5, 5 of5, 5 of 5, and 5 of 5 produce categories tested with ozone, chlorine 200 and2000 ppm, chloramine, and ethanol, respectively. Sonication, done in experimentswith chloramine and chlorine, significantly (p<0.05) improved the overalleffectiveness of these disinfectants by 0.2 logD. In practical terms, ozone wasthe least effective; and ethanol, the most effective and economical. Moreover,the results showed the limited effectiveness of these sanitation agents againstthe compact and resilient biofilms formed on surfaces and/or in crevices ofvegetables.