Wash, Rinse, and Sanitize with Three-compartment Sinks
The popularity of the three-compartment dishwashing process means a three-compartment sink is essential for nearly every restaurant. Most local health codes require them, and they're good pieces of equipment to have even if you also invest in a commercial dishwasher, since they provide an alternate dishwashing method if your warewashing equipment fails.
With prior approval, some health departments permit two-compartment sinks in locations with low dishwashing volume. However, some businesses may wish to go in the other direction and install a four-compartment sink, offering an extra bay for soaking utensils or a garbage disposal unit.
The three-sink method of manually washing dishes has been around for a while, and most people know the basics: wash, rinse, and sanitize. However, there are guidelines in place for each step to ensure that every dish emerges clean and sanitized. While each local health code varies, the FDA warewashing guidelines shown below are based on the 2017 FDA Food Code1 and can be used as a general overview of the process.
Warewashing with the 3-sink Method: First Steps
To properly execute the three-compartment dishwashing process, you must first prepare the area and the dishes to be washed. Your three-compartment sink can also be used to wash wiping cloths, clean produce, and thaw food, but it can't be used as a mop sink, for hand washing, or to wash maintenance tools. To prevent possible cross contamination, separate handwashing sinks and mop sinks must be provided for employees to wash their hands and rinse off maintenance equipment. Posting accessories such as handwashing signs and timers in the kitchen can help clearly indicate which sinks are for hand washing to eliminate confusion.
If food product is to be washed or thawed in the three-compartment sink, each basin must be emptied, washed, and sanitized before and after use. The same rules apply if wiping cloths are washed in the sink. Regardless for which purposes it has been used, each section of the three-bay sink should be thoroughly cleaned and sanitized before each dishwashing session, and it should also be completely emptied and cleaned every 4 hours.
The dishes also should be prepped before they're washed. Excess food must be scraped off into a trash can or food waste disposal. If you're using a four-section sink, the first section can be used during this prep period, either to house the food waste disposal or as an area to soak dishes to make removing caked-on food easier.
The temperature of detergent water is typically quite hot; to help protect your employees' skin from chemical cleansers and burns, have latex or neoprene dishwashing gloves and waterproof dishwasher aprons available for use. Equipment such as a dishtable can also be useful, giving employees a designated place to rest soiled dishes waiting to be cleaned.
Wash, Rinse, Sanitize: The 3-sink System
The three-compartment sink rules for manual warewashing revolve around three main steps: wash, rinse, and sanitize. Each step has specific FDA guidelines for sanitizer temperature and other variables, but the correct order of a three-compartment sink system never changes. Additional steps – such as scraping, pre-rinsing, and drying dishes – should also be included for optimal cleanliness.
- Prep: Scrape leftover food and residue off the dishes into a waste container or disposal system. Some operations feature a pre-rinse faucet to quickly rinse the dishes as well.
- Wash: Scrub dishes in the first sink compartment using warm, soapy water.
- Rinse: Remove soapy residue by rinsing dishes in clean, hot water in the second sink basin.
- Sanitize: Soak dishes in the third sink to sanitize them. Dishes can be sanitized with very hot water or a chemical sanitizing solution.
- Air dry: Place dishes on a self-draining rack or drainboard to dry. Never use any towel or other cloth to wipe dishes dry; doing so may contaminate the newly sanitized dishes.
FDA Warewashing Guidelines for the 3-sink Method
The FDA provides a number of additional guidelines for each step of the three-compartment dishwashing process, and it's important to also be aware of local health codes when setting up your dishwashing station. To streamline the process, more details on relevant FDA warewashing guidelines related to manual dishwashing are covered below.
Wash
The first step in the three-sink method, after prepping, is washing. It's important to note that washing dishes only makes them visibly clean, so it's vital to complete the process through sanitization. The first compartment in a three-bay sink should be filled with a solution of water and one of the following: soap, detergent, acid or alkaline cleaner, degreaser, or an abrasive cleaner. Depending on your local health codes, the water's minimum temperature will need to be between 95 and 120 degrees Fahrenheit. Keep a thermometer nearby to ensure the water is at the right temperature.
Depending on your restaurant's needs, a combination of glass brushes, sponges and scrubbers, dish cloths, and scrub brushes may come in handy.
Rinse
The second section in a three-compartment sink is dedicated to rinsing. The required temperature of the rinse water in this section may vary slightly in your local health code but is generally a minimum of 110 degrees Fahrenheit. This step uses clean water to remove surfactants and other cleaning agent residue from the first sink section. Wares can be rinsed by immersing them in the rinse basin or by spraying them with clean, hot water.
To ensure sanitary operation when immersing wares, water in the rinse basin must be drained and replaced with fresh water when it cools down below 110 degrees Fahrenheit, becomes visibly soapy or cloudy, or once every 4 hours during regular sink cleaning.
Sanitize
This third step in the three-sink method is arguably the most important. It ensures that all harmful microorganisms are killed and can be accomplished one of two ways.
- Chemical sanitizing means you use a chemical solution to kill bacteria. You can use EPA-approved water sanitizers, which usually come in dissolvable tablets, or a chlorine solution. If you use a water sanitizer, simply follow the manufacturer's directions. For a chlorine solution, consult your local health codes and the table below to help you determine the solution strength and sanitizer temperature you need and how long the dishes should soak. Chlorine test strips can also help confirm you have achieved the correct concentrations. In most cases, each dish will need to soak from 7 to 30 seconds to be completely sanitized.
- Hot water sanitization uses, as its name suggests, very hot water to kill all microorganisms on dishes. To use this method, the last section of your three-compartment sink must have a sanitizing sink heater installed. These heaters, made to be mounted underneath the sink, constantly circulate water to ensure it stays at or above 171 degrees Fahrenheit, the minimum sanitizing temperature. To decide which sanitizing sink heater you need, you'll need to know the size of your sink compartment in square inches.
All dishes and utensils sanitized with either method must be fully immersed in the hot water or chemical sanitizing solution for the required time period. Since the water in a hot water sanitizing system is kept at temperatures hot enough to burn skin, you'll need to outfit the sanitizing sink basin with a rack or basket for employees to comfortably lower and lift items in and out of the hot water.
Use a warewashing machine for items that are too large to be fully submerged in the sanitizing sink basin.
Restaurant Dishwashing Procedures for Drying Dishes
According to FDA warewashing guidelines, dishes must always air dry and are never to be dried with towels. For this reason, you'll likely need a drainboard on your sink. This drainboard must be self-draining to prevent the accumulation of water, and it should be large enough to enable all cleaned items to dry.
If you'll be washing a high volume of dishes, a drainboard may not be large enough to contain the cleaned dishes and enable adequate air flow for drying. To address this, you may want to add some drainage shelves to create more drying space in your dishroom.
After the dishes are dry, they can be placed in dish cabinets for clutter-free storage.
References
- Food Code 2017. U.S. Food and Drug Administration (FDA). Accessed August 2021.
