Submitted to: Meeting Abstract
Publication Type: Abstract only
Publication Acceptance Date: 3/10/2005
Publication Date: 7/15/2005
Citation: Annous, B.A., Sapers, G.M. 2005. Improved recovery procedure for evaluation of sanitizer efficacy in disinfecting contaminated cantaloupes (abstract). Institute of Food Technologists. Available:http://ift.confex.com/ift/2005/techprogram/paper_30723.htm. Interpretive Summary:
Technical Abstract: Fresh and fresh-cut cantaloupes have been associated with numerous outbreaks of salmonellosis. The attention of regulatory agencies and researchers has focused on the problem of melon decontamination. To conduct research in this area, it is necessary to artificially contaminate cantaloupes with a target organism in a manner which simulates natural contamination, and to use sampling and recovery methods that permit accurate enumeration of the target bacteria. Our objectives were to evaluate the effects of inoculation method, post-inoculation holding, and sampling method on recovery of bacteria from cantaloupe surfaces. Cantaloupes were spot or dip inoculated with suspensions of Salmonella Poona or Escherichia coli NRRL B-766 (a surrogate for S. Poona) containing 9-10 log CFU/ml. Inoculated cantaloupes were stored at 4 or 20°C for up to 72 h prior to treatments. Less than 1% of the cells applied to each spot on control cantaloupes could be recovered, and surviving population decreased further during storage. Bacterial survival during storage of melons was greater with dip than with spot inoculation. Similarly, bacterial survival following disinfection was greater with dip inoculation. About 2 logs of growth of Salmonella but not E. coli was found during post-inoculation storage at 20 C. Estimates of the attached microbial populations obtained with the new sampling methodology, using the entire rind of cantaloupes obtained with a mechanical peeler, were not significantly different (p<0.05) from those obtained by blending replicate rind plugs taken from multiple sites on the melon surface, the procedure used in previous studies, but the new procedure was simpler and substantially less tedious. Recovery was the same by both procedures for dip- and spot-inoculated samples and for post-inoculation holding times up to 72 h. Use of the new procedure would enable investigators to design melon experiments with more treatments or greater replication.