Dishwashing Temperature Guidelines for Food Safety

Dishwashers — also called warewashing machines — make life easier, especially when the alternative is washing dishes by hand.

However, they must reach certain temperatures to effectively kill bacteria and other disease-causing organisms called pathogens that can lead to foodborne illnesses.

This article explains everything you need to know about dishwashing temperature guidelines for food safety.

Dishwashing temperature guidelines

Ensuring that the wash and rinse water of your dishwasher reach a certain minimum temperature is just as important as cooking food to the proper minimum internal temperature.

Just as bacteria and other pathogens can survive on food that’s not cooked to its minimum internal temperature, they can also survive on dishes and utensils that aren’t washed and rinsed at the proper temperatures.

The minimum wash and rinse temperature depends on the type and whether it uses heat or chemicals to sanitize.

Those that rely on heat are called high-temperature dishwashers, while those that rely on chemicals are called low-temperature dishwashers.

This is because dishwashers that rely on heat must operate at a higher temperature than those that rely on chemicals to effectively kill pathogens.

Your dishwasher should have an attached plate that specifies its type and the required minimum temperature for the wash and rinse cycles.

Here are the wash cycle temperature guidelines for high-temperature dishwashers:

• 165ºF (74ºC) for a stationary rack, single-temperature machine
• 150ºF (66ºC) for a stationary rack, dual-temperature machine
• 160ºF (71ºC) for a single tank, conveyor, dual-temperature machine
• 150ºF (66ºC) for a multi-tank, conveyor, multi-temperature machine

For dishwashers that use chemicals to sanitize, the wash and rinse cycles should reach at least 120ºF (49ºC).

The temperature of the sanitizing rinse for high-temperature machines should be at least 165ºF (74ºC) for a stationary rack, single temperature machine, and 180ºF (82ºC) for all other machines.

These temperatures are hot enough to ensure that the surface temperature of the dishes reaches the minimum requirement of 160ºF (71ºC), but you should verify this by attaching a heat-sensitive test strip to a dish.

Regardless of the machine, the temperature of the sanitizing rinse should not exceed 194ºF (90ºC) since water begins to vaporize at this temperature, reducing its ability to properly sanitize.

Proper dishwasher maintenance and use

Regularly monitoring the temperature of your dishwasher cycles is crucial for effective cleaning and sanitizing — but it’s not enough.

You should also regularly monitor the water pressure gauges to ensure the dishwasher maintains adequate water pressure to effectively wash and sanitize.

Hard water deposits can form around the water jets and decrease water pressure.

The plate attached to the dishwasher that provides the temperature guidelines should also display the required pressure for the sanitizing rinse unless it’s designed to use only a pumped or recirculated sanitizing rinse.

Regularly empty any food particles from the scrap tray since they can block the water flow from jets and contribute to low water pressure.

You should also ensure the conveyor speed — if equipped — and the cycle times are maintained based on the machine’s data plate.

Proper washing and sanitizing cannot occur if the conveyor speed or cycle time is too quick.

Regularly monitor levels of the detergents and sanitizing solutions and ensure there isn’t a block in the dispensing line.

Dispensed detergents and sanitizers are usually stored in clear containers so you know they are being dispensed properly and when they run out.

Before loading dishes, always scrape or rinse off as much food residue as you can and avoid overloading the dishwasher to allow it to sanitize more effectively.

You may need to presoak items like utensils or pans to effectively remove food debris.

Make sure the dishes look clean after running them and allow them to air-dry completely before using or putting them away.

Three-compartment sink

Most kitchens must have a three-compartment sink to wash and sanitize any utensils or dishes that are too large to be run through the dishwasher — like large sheet pans.

Wash dishes in the first sink with hot, soapy water that is at least 110ºF (43ºC), rinse the dishes in the second compartment using clean water, and sanitize them in the third sink.

Like a dishwasher, you can sanitize dishes in a three-compartment sink using heat or chemicals.

If using heat to sanitize, the water must be a minimum of 171ºF (77ºC).

Because this temperature is hot enough to cause third-degree burns, you must use special equipment that allows you to immerse the dishes in the water and remove them safely.

Due to the safety concerns of using heat as a sanitizer, most food establishments rely on chemical sanitizers.

Similar to using a dishwasher, scrape off as much food debris as you can before washing and allow the dishes and utensils to air-dry completely before using or storing them.

Keep the sinks clean between uses.

If you use the sinks to wash produce or thaw food, you must clean and sanitize the sinks before and after.

The bottom line

Dishwashers vary widely by size, style, and method of sanitizing.

High-temperature dishwashers rely on heat to sanitize while low-temperature dishwashers rely on chemicals.

Operate high-temperature machines at 150ºF to 165ºF (66ºC to 74ºC) for the wash cycle and 165ºF to 180ºF (74ºC to 82ºC) for the rinse cycle.

Low-temperature machines should operate at a minimum of 120ºF (49ºC).

Regularly monitor the water pressure, conveyor speed — if equipped — and cycle time to ensure your dishwasher is operating effectively.

It’s important to know how to use a three-compartment sink to wash and sanitize items too large to fit in the dishwasher.