Tank-type ultrasonic washers for vegetables and fresh-cut produce · ultrasonic frequency and power used in published washing trials, ultrasound combined with chlorine, ozone or UV, and the US produce safety rule on wash water quality and water system maintenance
An industrial ultrasonic vegetable washer is a tank, which may have feed and discharge conveyors, in which produce is submerged in water while ultrasonic transducers create cavitation to help loosen soil and microorganisms. Ask three things first: which produce and throughput it must handle, whether ultrasound will be used with a sanitiser or other treatment, and how wash water quality will be kept within the rules that apply to your product.
Tank and conveyor washers for vegetables, fruit and fresh-cut produce that use ultrasound, with their wash water tanks, filtration and recirculation. Household ultrasonic produce cleaners, ultrasonic parts cleaners and acoustic soot blowers for boilers are outside this page.
CNFX editorial research · Sources checked October 12, 2026 · 5 sources
A 2022 study in Ultrasonics Sonochemistry combined ultrasound with chlorine for fresh-cut lettuce: an ultrasonic washer holding 8 L of water at 28 kHz and 300 W, with free chlorine at 10 ppm, described by the authors as a concentration recommended for industrial use. Rinsing afterwards with aqueous ozone instead of tap water gave lower counts of E. coli O157:H7 and Salmonella Typhimurium. The reduction exceeded 2 log CFU/g for both pathogens on day 0, without negative effects on lettuce quality. [1]
A 2024 study by an overlapping research group used ultrasonic washing at 40 kHz and 180 W combined with UV-LEDs as a chemical-free treatment for ready-to-eat produce. It reported reductions of 2.1–2.2 log CFU/g in Salmonella Typhimurium and E. coli O157:H7. [2]
These are laboratory trials on specific products and conditions. Ask a supplier for test results on your own produce, at your own throughput, and with the sanitiser you intend to use.
Give the supplier the produce types, piece size and fragility, the throughput, the ultrasonic frequency and power required (or ask for its recommendation with test data), any sanitiser, ozone or UV step, the water supply and recirculation, filtration and drainage, the feed and discharge conveyors, and the food safety rules that apply.
02
Manage wash water to the produce safety rule
Under US rule 21 CFR 112.44, agricultural water used during or after harvest in a way that directly contacts covered produce must have no detectable generic E. coli in 100 mL, and untreated surface water must not be used. Water applied to produce for washing or cooling is named as an example. The rule also covers water that contacts food contact surfaces. Untreated ground water used this way must initially be tested at least four times, using a minimum of four samples. [3]
Rule 21 CFR 112.42 requires agricultural water systems under the farm's control to be inspected at least once a year. They must be maintained so they are not a source of contamination, including regular monitoring and correction of significant deficiencies such as cross-connections and repairs to piping, tanks and treatment equipment. [4]
03
Keep wash-water chemicals within the US additive rule
21 CFR 173.315 lists the chemicals that may be used in washing fruits and vegetables: “Substances generally recognized as safe in food or covered by prior sanctions for use in washing fruits and vegetables”, sodium hypochlorite, potassium bromide, and surfactants such as sodium n-alkylbenzene-sulfonate up to 0.2% of wash water. For produce that is not a raw agricultural commodity — fresh-cut items, for example — peroxyacetic acid may be used up to 80 ppm, with hydrogen peroxide up to 59 ppm and HEDP up to 4.8 ppm. [5]
The rule requires chemicals to be used at no more than the minimum needed for their effect, and washing with the GRAS, listed-surfactant and flume-water substances must be followed by a potable-water rinse to remove residues as far as possible. A washer that relies on ultrasound to cut sanitiser demand still has to dose and record its chemistry against these limits. [5]
Editorial calculation: the 2022 lettuce trial above used free chlorine at 10 ppm with 28 kHz, 300 W ultrasound in 8 L; for a fresh-cut line using peroxyacetic acid instead, the 80 ppm ceiling is 8 times that dose, so specify a dosing pump and concentration monitor that hold the set point below the limit. [1][5]
04
Transducers, tank, sanitiser dosing, filtration and final rinse
Only the transducer row carries machine settings from the trials (28 kHz/300 W and 40 kHz/180 W); the dosing, filtration and rinse rows are fixed by the US rules rather than by the washer maker. [1][2][5][3]
Explore company information and manufacturing capabilities, then discuss the scope of your project with a relevant supplier.
Share this page
Compiled and source-reviewed by the CNFX editorial team.
Each manufacturer above links to the page on that company's own website where the product is listed, with the date we checked it. How we source and review
· Page last updated 13 October 2026
Buyer questions
What ultrasonic settings were used in published produce-washing trials?
One study used 28 kHz and 300 W with 10 ppm free chlorine on fresh-cut lettuce. Another used 40 kHz and 180 W combined with UV-LEDs. [1][2]
What water quality does the US rule require for produce washing?
No detectable generic E. coli in 100 mL, and no untreated surface water, under 21 CFR 112.44. [3]
How much peroxyacetic acid can be used in produce wash water?
For produce that is not a raw agricultural commodity, 21 CFR 173.315 allows up to 80 ppm peroxyacetic acid, with hydrogen peroxide up to 59 ppm. [5]
Sources and what still needs a direct check
Sources checked 2026-10-12. The two research articles are open-access papers in Ultrasonics Sonochemistry read via PubMed Central. The eCFR sections are current US produce safety rules.
