Inactivation of Escherichia coli O157:H7 in biofilm on food-contact surfaces by sequential treatments of aqueous chlorine dioxide and drying

• Published in: International journal of food microbiology Vol. 191; pp. 129 - 134
• Main Authors: Bang, Jihyun, Hong, Ayoung, Kim, Hoikyung, Beuchat, Larry R., Rhee, Min Suk, Kim, Younghoon, Ryu, Jee-Hoon
• Format: Journal Article
• Language: English
• Published: Amsterdam Elsevier B.V 17.11.2014; Elsevier
• Subjects: Anti-Infective Agents - pharmacology; Biofilm; Biofilms - drug effects; Biological and medical sciences; Chlorine Compounds - pharmacology; Chlorine dioxide; Colony Count, Microbial; Desiccation; Drying; Escherichia coli - drug effects; Escherichia coli O157 - drug effects; Escherichia coli O157:H7; Food Handling - instrumentation; Food industries; Food microbiology; Food Microbiology - methods; Food-contact surface; Fundamental and applied biological sciences. Psychology; Glass; Microbial Viability - drug effects; Oxides - pharmacology; Plastics; Sodium Hypochlorite - pharmacology; Stainless Steel; Water; Wood - microbiology; Biofilm; Chlorine dioxide; Escherichia coli O157:H7; Food-contact surface; Drying; Food contact; Escherichia coli; Bacteria; Inactivation; Contact surface; Surface treatment; Enterobacteriaceae
• ISSN: 0168-1605; 1879-3460
• DOI: 10.1016/j.ijfoodmicro.2014.09.014

We investigated the efficacy of sequential treatments of aqueous chlorine and chlorine dioxide and drying in killing Escherichia coli O157:H7 in biofilms formed on stainless steel, glass, plastic, and wooden surfaces. Cells attached to and formed a biofilm on wooden surfaces at significantly (P≤0.05) higher levels compared with other surface types. The lethal activities of sodium hypochlorite (NaOCl) and aqueous chlorine dioxide (ClO2) against E. coli O157:H7 in a biofilm on various food-contact surfaces were compared. Chlorine dioxide generally showed greater lethal activity than NaOCl against E. coli O157:H7 in a biofilm on the same type of surface. The resistance of E. coli O157:H7 to both sanitizers increased in the order of wood>plastic>glass>stainless steel. The synergistic lethal effects of sequential ClO2 and drying treatments on E. coli O157:H7 in a biofilm on wooden surfaces were evaluated. When wooden surfaces harboring E. coli O157:H7 biofilm were treated with ClO2 (200μg/ml, 10min), rinsed with water, and subsequently dried at 43% relative humidity and 22°C, the number of E. coli O157:H7 on the surface decreased by an additional 6.4CFU/coupon within 6h of drying. However, when the wooden surface was treated with water or NaOCl and dried under the same conditions, the pathogen decreased by only 0.4 or 1.0logCFU/coupon, respectively, after 12h of drying. This indicates that ClO2 treatment of food-contact surfaces results in residual lethality to E. coli O157:H7 during the drying process. These observations will be useful when selecting an appropriate type of food-contact surfaces, determining a proper sanitizer for decontamination, and designing an effective sanitization program to eliminate E. coli O157:H7 on food-contact surfaces in food processing, distribution, and preparation environments. •E. coli O157:H7 form a biofilm on stainless steel, glass, plastic, and wooden surfaces.•Attachment and biofilm formation by E. coli O157:H7 were enhanced on wooden surfaces.•ClO2 was superior to NaOCl in inactivating E. coli O157:H7 cells in a biofilm.•Cells on wooden surface were more resistant to sanitizers compared to other surfaces.•Combination of ClO2 and drying showed synergistic lethal effects on E. coli O157:H7.