Comparative efficacies of various chemical sanitizers for warewashing operations in restaurants

This study compared the efficacies of two traditional with two experimental sanitizers for use in tableware cleaning operations in restaurants and foodservice operations. This was done by investigating the maximum number of cleaning cycles that a single recommended quantity of each sanitizer could treat and still produce a 5-log bacterial reduction on test tableware items. Cream cheese and whole milk were inoculated with Escherichia coli K12 and Listeria innocua and subsequently used for contamination of the tableware items. These items were washed with automatic (49 °C) and manual (43 °C) dishwashers then treated with electrolyzed-oxidizing water (EO), quaternary ammonium compound, sodium hypochlorite and an acidic sanitizer. For the lowest efficacies, after six and eight manual washing cycles in the same solution, ≥5 log reductions were achieved on both E. coli K12 contaminated trays and plates, respectively, exposed to the chlorine and quaternary ammonium sanitizers. For automatic washing with chlorine sanitizer, the minimum wash cycles for the bacteria were seven and nine for the trays and plates, respectively. For drinking glasses contaminated with bacteria, 14 and 17 washing cycles produced ≥5 log reductions for manual and automatic washings, respectively.