Adding Sanitizer to Produce Wash Water

Food-grade sanitizers added to produce wash water may reduce the risk of spreading pathogens.

Image source: Michigan On-Farm Produce Safety

Adding Sanitizer to Produce Wash Water

Do you use sanitizer in your produce wash water? Adding an antimicrobial product to your post-harvest water can provide several benefits to the overall quality of the produce. The decision of whether or not to add a sanitizer to post-harvest water, and which specific sanitizer to use, can depend on several factors. 

Sanitizer vs. Plain Water

The first question we need to ask is, what’s wrong with using plain ol’ water to rinse produce? The answer can get complicated. The FSMA Produce Safety Rule requires that any water used during or after harvest must be of safe and adequate sanitary quality for its intended use. In short, this means that any water used for washing produce must be tested for the absence of detectable generic E. coli, and it must be maintained at that level of cleanliness. 

Here’s where it gets complicated. Starting with clean water is simple enough, and if the wash water used is single-spray, the chances of cross-contamination are pretty minimal. Using plain water for spraying produce, so long as it meets the initial water quality requirements, is probably fine in most instances. 

Batch and recirculated water systems are not as straightforward, however. How do we verify that no cross-contamination has occurred once outside objects (i.e., produce) are added to the water? It is highly unrealistic that farms would have the capacity to perform mid-wash water testing, or that results would be ready in time to act. It is equally improbable that farms could perform adequate product testing before washing to catch potential cross-contamination risks. 

So, how do we maintain water cleanliness in batch and recirculated water? That’s where sanitizer comes in! Sanitizers used in produce wash water are pesticides designed to kill bacteria and other microorganisms present in the water. Adding sanitizer to wash water does not necessarily sanitize the produce being washed; rather, the sanitizer’s job in this application is to help keep the water clean. In doing so, bacteria that may have been introduced to the water from one piece of produce are eliminated before they can persist, multiply, and spread to the other produce in the wash tank. 

Besides Keeping Clean Water Clean, What Else Can A Sanitizer Do?

Again, the job of sanitizer in wash water is not specifically to sanitize produce. However, you will likely still see some benefits of a reduced pathogen load after using sanitized water. Washing or rinsing produce with water treated with a sanitizer can reduce the initial load of foodborne pathogens and spoilage organisms while maintaining the nutritional content of the produce. Fewer pathogens and spoilage organisms can mean better quality and longer shelf life for the produce - an overall win for farms.

Beyond foodborne pathogens and spoilage organisms, sanitizers added to postharvest water can help treat and reduce the presence of certain diseases, such as Phytophthora blight, a water mold affecting cucumber crops, or black rot in sweet potatoes. The use of food-grade sanitizers post-harvest does not need to be limited to the wash water tank, either. Sanitizers used in post-harvest for hydrocooling, sorting, and waxing crops can reduce microbial load and lower the risk of foodborne illnesses. 

Which Sanitizers Are Allowed In Produce Wash Water?

First, let’s define what can and cannot be added to wash water or any other water used in post-harvest activities. Not all sanitizers are created equal, and there are hundreds of sanitizer products on the market. In this context, we need to follow two basic rules: 

1. The sanitizer should have an EPA pesticide registration number, and,

2. The EPA label should include specific instructions for the washing of produce.

EPA labels are the law and must be followed whenever a sanitizer is used. The EPA label provides important information, including dosing, mixing, application, monitoring, and disposal instructions. Often, the entire label does not fit on a regular bottle of sanitizer, so it is best practice to always search the product’s EPA Registration Number to access the full label. For an easy cheat sheet on EPA-Labeled Sanitizers for Produce, the Produce Safety Alliance has already done the heavy lifting for you. 

How Do I Choose A Sanitizer? 

If you opened the previous link on sanitizers for produce, you may have noticed that there are many approved options on the market. Choosing the right one for you probably depends on several factors, including price, availability, active ingredient, material compatibility, types of produce being washed, and more. Michigan State University Extension offers a Comparison of Various Sanitizers (See below) that can aid in the decision-making. Ultimately, if the sanitizer is labeled for washing fruits and vegetables, the choice is yours. 

Want to learn more? 

Michigan Produce Safety Technicians are ready to help you meet your on-farm produce safety goals. We will work with you to identify, manage, and minimize risks to food safety on your farm, and help you create a comprehensive food safety plan to prepare you for an MI Produce Safety Risk Assessment Certificate. Working with produce safety technicians is always free and confidential, and there is no cost to applying for the certificate. Click here to get started.

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Article by Landen Tetil, Produce Safety Technician