Checking Sanitizing Capabilities

of Dishwashers in Food Facilities

Chemical and high temperature dishwashers are very helpful and save time during the dish washing procedure.  These machines are designed to take all of the dishes/utensils placed inside them through the entire wash-rinse-sanitize process.  If working correctly, the dishwasher will wash the dishes using a soap or detergent, rinse the dishes with clear water, and sanitize the dishes using a chemical (usually chlorine) sanitizer or, in the case of a high temperature model, hot water released from the manifold at 171oF that reaches the dishes at the disinfecting temperature of 160oF.

If you are using one of these machines in your facility it is important to test the unit every day.  Often times the manufacturer of the machine will come out to service the machine on a weekly or monthly basis.  THIS IS NOT AN ADEQUATE TESTING METHOD.  Someone employed by the facility should test the machine at least once a day to make sure it is sanitizing correctly.  In addition, all employees that use the machine should also be aware of how to test the sanitizer level.

o   To check a chemical dishwasher you should run a “test” load of dishes through the machine.  At the end of the cycle use a piece of sanitizer testing paper or a sanitizer testing strip to test the concentration of the final rinse water.  The test should read a minimum of 50 parts per million chlorine sanitizer.  If the machine uses a chemical sanitizer other than chlorine, check the manufacturer’s instructions regarding sanitizer concentration levels. 

o   To check a high-temperature dishwasher the employee should watch the temperature dials on the machine during an entire cycle.  When the machine is in the rinse portion of the cycle make sure that the temperature dial reaches 171oF.  If a high temperature probe thermometer is run through the machine with the dishes it should come out reading at least 160oF.

The beginning of the workday is the best time to check the machine.  If a problem with the machine is detected, it is early enough to call for repairs.  It is in the best interest of the facility to keep a record of when and by whom the dishwasher was tested.  An example log is provided on the back of this bulletin.

If the test reveals that the machine is not sanitizing the dishes/utensils with appropriate chemical levels (e.g. 50ppm chlorine) or 171oF water, immediately stop using the machine and contact a repair company.  Until the repairs have been made and another test reveals that the machine is sanitizing correctly, use an alternative dishwashing method, such as the three compartment sink, where each dish or utensil is washed, rinsed, and sanitized by hand.

No dishwasher may be used unless it is working properly and sanitizing at the appropriate levels.

Also, when a machine fails a sanitizer test, all of the dishes that have been run through the machine since it last passed the test must be sanitized again before being used.

*Note: Any equipment, utensils, or dishes too large to fit in the dishwasher will need to be cleaned and sanitized in place.  See Informational Bulletin 54 on “in-place sanitizing”.

*Document available in an alternate format upon request

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