Does the sanitizer in wash water kill pathogens on the produce?

Its main job is protecting the water. Extension guidance describes wash water sanitizers as killing what comes off the produce before it can spread to other produce or equipment. Reductions on the produce surface itself are a separate question.

Does the FSMA Produce Safety Rule require chlorine in wash water?

No. Subpart E does not name a sanitizer. It requires harvest and post-harvest water to have no detectable generic E. coli in 100 mL, and any treatment you use has to be effective and monitored often enough to keep the water consistently safe.

Can a waterless treatment replace a produce wash line?

It can replace a wash step whose job is microbial control. It does not remove soil, so if a step is there to clean the product, you still need water or brushing before treatment. Clean Works systems can be built into a line or used as a standalone step. Our team looks at line layout, product flow and throughput before designing one.

What log reduction can I expect on fresh produce with Clean Works?

Published third-party results on fresh produce are mostly between 2 and 3.5 log, depending on the product and organism. Performance varies with the product surface, treatment conditions and how the product is presented.

Chlorine vs. Peracetic Acid vs. Waterless Produce Treatment

Strawberries, blueberries, red apples and lettuce on a stainless-steel table in a produce packing facility

Produce wash guide

Chlorine is cheap and familiar, but organic matter and high pH use it up fast. Peracetic acid holds up better in dirty water and needs no rinse, but it costs more and is capped at 80 ppm. A waterless gas-phase step has no wash water to dose, test or change, but it does not clean soil off the product. The right choice depends on how your product arrives, what it can tolerate and what your buyers ask for.

See the comparison Talk to our team

Published by Clean Works · Last reviewed November 13, 2026 · 6 sources

Side by side

The three options at a glance.

How chlorine, peracetic acid and a waterless gas-phase step compare for fresh produce
	Chlorine	Peracetic acid (PAA)	Waterless gas-phase
How it works	Free chlorine, mostly hypochlorous acid, kills microbes in the wash water.	Peroxyacetic acid oxidizes microbes in the wash water.	UV-C, hydrogen peroxide and ozone form hydroxyl radicals that act on the product surface. There is no wash water.
Typical use	50–200 ppm with 1–2 minutes of contact, following the product label.	No more than 80 ppm in wash water for processed produce (21 CFR 173.315).	In many applications, treatment takes 30 seconds or less.
What weakens it	Soil and plant debris, pH above 7.5 and warm water.	Heavy organic load (less than chlorine), copper, and it breaks down quickly.	It is not a cleaning step. Soil and debris need to come off first.
What you monitor	Free chlorine and pH, frequently, plus a water change schedule.	PAA concentration, frequently, plus water cloudiness.	System settings. There is no water at this step to test.
Rinse and residue	A potable rinse is often recommended. Chlorate residues matter for some export markets.	No potable rinse required before sale.	Radicals break down into water and oxygen. No residue.
Equipment	Corrosive to stainless steel and aluminum.	Not corrosive to equipment. Strong vinegar smell, needs ventilated storage.	A treatment chamber, in the line or as a standalone step.

Start here

What a wash water sanitizer is really for.

It is easy to assume the sanitizer in a flume or dump tank is cleaning the produce. Extension guidance describes its main job differently: it kills what washes off one piece of produce before that can land on the next piece, or on the equipment.

That matters when you compare options. Chlorine and PAA are mostly protecting the water. A waterless step has no shared water to protect, so it is judged on a different question: how much it reduces on the product surface itself.

Chlorine

Cheap and well understood, but easy to lose.

Chlorine is the default for a reason. It is inexpensive, widely available and most produce teams already know how to use it. Extension sources usually recommend 50 to 200 ppm with one to two minutes of contact, at a pH of roughly 6.5 to 7.5. Above pH 7.5 more of it turns into the weaker hypochlorite ion, and below 6.5 the water starts to corrode equipment.

The bigger problem is organic matter. Every bit of soil and plant debris uses up free chlorine. In a 2025 Purdue Extension test, a 100 ppm solution dropped to about 1.8 ppm after 1% vegetable matter was added. A tank that tested fine at the start of a shift can be doing very little an hour later, which is why frequent free chlorine and pH checks are part of using it.

If you export, check your buyers' markets too. The EU set maximum residue levels for chlorate in 2020, and the European Commission notes that chlorate comes from chlorine disinfectants used in water treatment and food processing.

Peracetic acid

Tougher in dirty water, at a higher price.

Peracetic acid (PAA, also called peroxyacetic acid) is the usual step up from chlorine. It keeps more of its activity when organic load is high, it is not corrosive to equipment, and FDA does not require a potable rinse before sale.

There are trade-offs. PAA costs more than chlorine, it breaks down quickly so concentration still has to be checked often, it has a strong vinegar smell and it loses effectiveness around copper. For fruits and vegetables that are not raw agricultural commodities, such as fresh-cut, FDA caps it at 80 ppm in wash water, with hydrogen peroxide no higher than 59 ppm.

Waterless gas-phase

Taking the water out of the step.

A gas-phase system like Clean Works treats the product inside a chamber instead of in a tank. UV-C light activates hydrogen peroxide and ozone to form hydroxyl radicals, which damage the cell membranes, proteins and DNA of microbes on the surface, then break down into water and oxygen. The technology page walks through each step.

Because there is no shared water, there is nothing to carry contamination from one piece to the next, and nothing to dose, test or change at that step. That is the main reason to consider it, along with avoiding a wet product going into packing or freezing.

It is not the answer to everything. A gas-phase step does not remove soil, so heavily soiled product still needs cleaning first. Results also depend on the product. On fresh produce, our published reductions are mostly between 2 and 3.5 log, not the 5-log figures you will see for smooth surfaces. You can see every result on the results page.

Regulation

What the FSMA Produce Safety Rule asks of your water.

Subpart E of the Produce Safety Rule covers harvest and post-harvest water. It does not tell you which sanitizer to use. It does set the standard the water has to meet and how you manage it:

No detectable generic E. coli in 100 mL of harvest or post-harvest water, and no untreated surface water (§ 112.44(a)).
For recirculated or reused water, a water change schedule, visual checks for soil and debris, and temperature control suited to the commodity (§ 112.44(d)).
Any treatment has to be effective and monitored often enough to keep the water consistently safe (§ 112.46).
If the water is not safe, you must stop using it immediately (§ 112.45(a)).

Regulation

Where a waterless step fits in.

A waterless treatment step uses no water, so there is no water at that step to test, treat or change. It does not take the rest of your operation out of the rule. Any water you still use elsewhere, and every other part of the Produce Safety Rule, still applies. Compliance dates passed in January 2023 for larger farms, January 2024 for small businesses and January 2025 for very small businesses.

Clean Works results

What a waterless step has done on fresh produce.

Third-party results from the Clean Works validation library. Reductions vary with the product surface, the organism, treatment conditions and how the product is presented.

Apples

Product: Whole apples
Target: Listeria
Result: 2.32 log reduction

Blueberries

Product: Fresh blueberries
Target: Salmonella
Result: 2.0 log reduction

Peaches

Product: Fresh peaches
Target: Listeria
Result: 2.1 log reduction

Tomatoes

Product: Whole tomatoes
Target: Salmonella | E. coli
Result: 2.22 | 3.55 log reduction

Lettuce

Product: Whole leaf iceberg
Target: E. coli
Result: 2.47 log reduction

Mushrooms

Product: White mushrooms
Target: Listeria
Result: 2.02+ log reduction

How a waterless produce step works

Before you decide

Six questions to ask about your own line.

How dirty is the product when it reaches this step?Heavy soil quickly uses up chlorine. A gas-phase step needs the soil removed first.
Is the step there to clean, or to control microbes?If it is mostly cleaning, you still need water or brushing. If it is mostly microbial control, a waterless step can take its place.
Does getting the product wet cause problems later?Extra drying, shorter shelf life or ice on frozen product are all costs of a wet step.
Where do you ship?Some export markets set chlorate residue limits, which can push teams away from chlorine.
Who checks the water, and how often?Chlorine and PAA both need frequent concentration checks to stay effective. A waterless step does not.
How much water and wastewater do you handle today?Water use, treatment and disposal costs are part of the real cost of a wash.

FAQs

Produce wash questions.

It depends on your water. PAA holds up better when organic load is high, does not corrode equipment and needs no potable rinse. Chlorine is cheaper and familiar, but soil and high pH use it up quickly, so it needs closer monitoring.

Sources

Where these facts come from.

Outside facts on this page were checked against these sources on November 13, 2026. Clean Works figures come from our published validation results.

Requirements for Harvest and Post-Harvest Agricultural Water in Subpart EU.S. Food and Drug Administration
21 CFR 173.315: Chemicals used in washing or to assist in the peeling of fruits and vegetablesCode of Federal Regulations
Farm Food Safety: Choosing a Sanitizer for Washing Fresh Produce (HGIC 3644)Clemson Cooperative Extension
Chlorinated Water Sanitation of Leafy Green Vegetables for Fresh Produce Processors (AEX-262)Ohio State University Extension
Understanding the Impact of Organic Matter on Free Available Chlorine in Postharvest WaterPurdue University, Facts for Fancy Fruit
Chlorate: maximum residue levelsEuropean Commission

Compare it on your product

See how a waterless step would work on your line.

Tell us what you run and how you wash it today. We'll send the results that match your product and an honest view of whether a waterless step makes sense for you.

Results for products like yours
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Chlorine vs. peracetic acid vs. waterless treatment for produce