Decontamination of Strawberries Using Batch and Continuous Chlorine Dioxide Gas Treatments
Abstract:Efficacy of chlorine dioxide (ClO2) gas in reducing Escherichia coli O157:H7 and Listeria monocytogenes on strawberries was determined using batch and continuous flow ClO2 gas treatment systems. Effects of continuous ClO2 gas treatment on total aerobic plate count, color, and residual ClO2 and chlorite on strawberries were also evaluated. Strawberries were spot inoculated with 7 to 8 log CFU per strawberry of each pathogen (E. coli O157:H7 and L. monocytogenes), stored for 1 day at 4°C, and treated at 22°C and 90 to 95% relative humidity with 0.2 to 4.0 mg/liter ClO2 gas for 15 or 30 min using a batch treatment system or with 0.6, 1.8, and 3.0 mg/liter for 10 min using a continuous treatment system. Surviving microbial populations were determined using a membrane-transfer plating recovery method. Increased ClO2 gas concentrations resulted in increased log reductions of each pathogen for both the batch and continuous systems. A batch treatment of strawberries with 4 mg/liter ClO2 for 30 min and continuous treatment with 3 mg/liter ClO2 for 10 min achieved greater than a 5-log reduction for both E. coli O157:H7 and L. monocytogenes. After continuous exposure to 3.0 mg/liter ClO2 gas for 10 min followed by 1 week of storage at 4°C, no aerobic microorganisms were detected and the color of the strawberry surface did not change significantly (P > 0.05). Residues of ClO2 and chlorite on strawberries after the treatment were 0.19 ± 0.33 mg ClO2 per kg and 1.17 ± 2.02 mg Cl2 per kg, respectively, whereas after 1 week of storage no ClO2 residues were detected and residual chlorite levels were down to 0.07 ± 0.12 mg Cl2 per kg. These results suggest that ClO2 gas treatment is an effective decontamination technique for improving the safety of strawberries while extending shelf life.
Document Type: Research Article
Affiliations: Department of Food Science, Purdue University, West Lafayette, Indiana 47907-1160, USA
Publication date: November 1, 2004
More about this publication?
- IAFP Members with personal subscriptions to JFP Online: To access full-text JFP or JMFT articles, you must sign-in in the upper-right corner using your Ingenta sign-in details (your IAFP Member Login does not apply to this website). The Journal of Food Protection (JFP) is a refereed monthly publication. Each issue contains scientific research and authoritative review articles reporting on a variety of topics in food science pertaining to food safety and quality. The Journal is internationally recognized as the leading publication in the field of food microbiology with a readership exceeding 11,000 scientists from 70 countries. The Journal of Food Protection is indexed in Index Medicus, Current Contents, BIOSIS, PubMed, Medline, and many others.
Print and online subscriptions are available to IAFP Members and institutional subscribers. IAFP Members with a subscription to JFP Online will have access to all available JFP and JMFT content. Online visitors who are not IAFP Members or journal subscribers will be charged on a pay-per-view basis. Membership and subscription information is available at www.foodprotection.org.
- Information for Authors
- Submit a Paper
- Subscribe to this Title
- Membership Information
- Information for Advertisers
- ingentaconnect is not responsible for the content or availability of external websites