Effects of food composition on the inactivation of foodborne microorganisms by chlorine dioxide
2009
Vandekinderen, I. | Devlieghere, F. | Van Camp, J. | Kerkaert, B. | Cucu, T. | Ragaert, P. | De Bruyne, J. | De Meulenaer, B.
Chlorine dioxide (ClO₂) is a strong oxidizing agent that can be applied in solution as well as in the gaseous state. It has bactericidal, fungicidal and viricidal properties. Several food-related microorganisms, including Gram-negative and Gram-positive bacteria, yeasts, mould spores and Bacillus cereus spores were tested for their susceptibility to 0.08 mg/L gaseous ClO₂ during 1 min at a relative humidity of 90%. In this screening, the resistance of the different groups of microorganisms towards gaseous ClO₂ generally increased in the order Gram-negative bacteria, Gram-positive bacteria, yeasts and mould spores and Bacillus cereus spores. With this treatment, reductions of microbial numbers between 0.1 and 3.5 log cfu/cm² could be achieved. The effects of the food components starch, fat, protein and NaCl on the antimicrobial activity of gaseous ClO₂ were also evaluated. Soluble starch, corn oil, butter, whey protein isolate and NaCl were added in incremental concentrations to portions of an agar medium. Then, plates of the supplemented agars were inoculated with Leuconostoc mesenteroïdes at numbers of 4 log cfu/cm² and subsequently treated with ClO₂. Both soluble starch and NaCl did not have an effect on the antimicrobial efficiency of ClO₂. However, butter, corn oil or whey protein in the agar almost eliminated the antimicrobial effect of ClO₂. In corn oil-water emulsions treated with gaseous ClO₂ the peroxide value increased significantly, indicating the formation of primary oxidation products. Similarly, a treatment with ClO₂ increased the protein carbonyl content and induced the transformation of SH-groups to -S-S-groups in whey protein. The findings suggest that gaseous ClO₂ will be a highly effective decontaminating agent for carbohydrate-rich foods, but that it would be less effective for the decontamination of high-protein and fatty foods.
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