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Decontamination of strawberries using batch and continuous chlorine dioxide gas treatments.

Author(s) : HAN Y., SELBY T. L., SCHULTZE K. K., et al.

Type of article: Article

Summary

The 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. The effects of continuous ClO2 gas treatment on the total aerobic plate count, colour, and residual ClO2 and chlorite on strawberries were evaluated. Strawberries were spot inoculated with 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/litre ClO2 gas for 15 or 30 min. using a batch treatment system or with 0.6, 1.8, and 3.0 mg/litre 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 reductions of each pathogen for both the batch and continuous systems. A batch treatment of strawberries with 4 mg/litre ClO2 for 30 min. and continuous treatment with 3 mg/litre 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/litre ClO2 gas for 10 min followed by 1 week of storage at 4 °C, no aerobic microorganisms were detected and the colour of the strawberry surface did not change significantly. Residues of ClO2 and chlorite on strawberries after the treatment were 0.19 plus or minus 0.33 mg ClO2 per kg and 1.17 plus or minus 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 plus or minus 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.

Details

  • Original title: Decontamination of strawberries using batch and continuous chlorine dioxide gas treatments.
  • Record ID : 2005-1308
  • Languages: English
  • Source: Journal of Food Protection - vol. 67 - n. 11
  • Publication date: 2004/11

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