Ultrasonic humidifiers are gaining attention in the U.S. retail market for their ability to keep produce and perishable goods hydrated. However, their use can introduce significant health risks, water waste, and high maintenance demands. An exciting alternative to ultrasonic humidifiers is FogMist, offering the benefits of ultrasonic humidification without the significant health risks.

By addressing the limitations of ultrasonic humidifiers, FogMist ensures product freshness while minimizing operational challenges. Retailers can benefit from a solution that’s both adaptable across departments and easy to manage, supporting consistent produce quality, reduced shrinkage, and improved sustainability. Read on to understand the pros and cons of ultrasonic humidifiers versus FogMist.

How Ultrasonic Systems Work

Ultrasonic humidifiers operate on a relatively simple mechanical principle. Inside the unit, a metal diaphragm vibrates at an ultrasonic frequency of millions of times per second. High-speed vibrations strike the water, breaking it into micro-fine droplets—a fine mist that the unit then fans out into the display area.

Provide Localized Humidity in Display Areas

Ultrasonic units are often praised for their ability to deliver moisture exactly where it’s needed. This localized approach allows retailers to target specific areas in a produce rack that might be prone to drying out due to high airflow.

Additionally, because the mist is generated via mechanical vibration rather than heat, it is cool to the touch and doesn't raise the temperature of the refrigerated display case.

Help Maintain Turgor Pressure

Turgor pressure is the force of water against the cell walls of a plant, which keeps it upright and crunchy. When a vegetable loses moisture to the dry air of a grocery store, it wilts. Ultrasonic systems provide a dense fog that coats the surface of the produce, slowing down the rate of evaporation and helping the plant retain its internal moisture. This keeps the items looking garden-fresh for several days longer than they would in a dry case.

Simple to Operate, but Requires Frequent Refills

On the surface, ultrasonic units appear user-friendly. Many are plug-and-play devices that do not require complex installations. However, this simplicity can also pose challenges. Because these units often rely on internal reservoirs rather than a continuous, filtered water line, store associates must spend significant time monitoring and refilling them with water. If a reservoir runs dry, the produce begins to dehydrate immediately, negating the benefits of the system.

Liabilities: Bacteria, Water Waste, Cost and Maintenance

While effective at adding moisture, ultrasonic systems can create an environment that poses significant health risks.

Very High Initial Costs and Maintenance Requirements

Despite their advantages, ultrasonic humidity systems require significant investment in terms of cost and time:

• The initial purchase price of ultrasonic systems is usually higher than that of other types of humidifying and misting systems.
• The transducers in ultrasonic systems are highly sensitive to mineral buildup from hard water. Without daily cleaning and the use of demineralized water, these transducers fail frequently. In a retail setting, such failures can result in high labor and maintenance costs.

The Reservoir and Delivery Tubing Often Contain Stagnant Water

One of the biggest dangers of ultrasonic technology is its tendency to harbor pathogens. Because these systems involve standing water in reservoirs, they become breeding grounds for pathogens, creating biofilm that lines the reservoirs. Unlike evaporative systems, ultrasonic vibrations disperse everything present in the reservoir into the air, including bacteria. The responsibility for cleaning water reservoirs rests with store employees, making health risks susceptible to human error.

Droplet Size Is Inhalable

The droplets from ultrasonic systems are typically between 1 and 5 microns—small enough to be inhaled. If the water or reservoir is contaminated, the system acts as a nebulizer for pathogens to be inhaled and directly enter lung cells, posing critical health risks, including outbreaks of Legionnaires' disease.

Insufficient Moisture Throughout The Case

Ultrasonic fog often lacks the pressure or directional control to permeate the entire depth of a display case. Because grocery stores are high-flow environments, any air movement can misdirect the mist away from the produce, leaving the food dry. Non-directional fog drifts away and evaporates without reaching the lower shelves in the case.

Three FogMist Safety and Efficiency Advantages

FogMist is engineered to deliver controlled and effective hydration, as with ultrasonic systems, without the risks common to them. Its technology reduces bacterial proliferation, minimizes water use, and lowers maintenance needs. Some of the advantages of FogMist over ultrasonic humidifiers include:

1. Droplet Size Cannot Be Inhaled

The primary differentiator for FogMist is the management of droplet size and water purity. The system is designed so that the particles are optimized for plant absorption but are large enough that they are not an inhalation risk for pathogens. Additionally, FogMist systems do not utilize a water reservoir, so there is no risk of contamination.

2. Water Savings

Water conservation is a growing concern for global retailers. FogMist is highly efficient, often achieving greater water savings than traditional misters. By using high-pressure nozzles, the system creates a fog that is more effective at lower volumes. This feature prevents over-wetting and directly translates to lower utility bills.

3. Simplified Maintenance for Smoother Store Operations

FogMist maintenance is simple. Additionally, our team of expert technicians operates nationwide to provide in-house installation, maintenance, and service for their misting, humidification, and night cover systems.

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Adaptability across Departments

FogMist precisely adjusts humidity to the unique needs of each grocery area, ensuring optimal conditions for a wide range of items with minimal effort. FogMist’s versatility allows it to be customized for various departments:

• Produce: Maintains the crispness of leafy greens and prevents the weight loss that leads to profit shrinkage.
• Floral: Delicate flowers require high humidity but can be ruined by heavy water droplets. FogMist keeps petals hydrated without causing spotting or mold.
• Seafood and meat: High-quality proteins lose their luster and weight when exposed to the dry air of a service case. FogMist creates an invisible blanket of moisture that preserves the bloom of red meat and the glistening appearance of fresh fish.

Educating Retailers on System Choice

To make informed decisions about hydration systems, retailers need clear guidance. Understanding the limitations of ultrasonic units and the benefits of FogMist is essential for operational efficiency and product quality. Education should focus on:

• Training on safe and efficient system use, including bacterial safety
• Choosing a system that allows staff to focus on customers, not scrubbing or refilling water tanks
• Using systems that align with corporate mandates for water and energy reduction to accomplish sustainability goals
• Using the system with an emphasis on ROI, safety, shrinkage reduction, sustainability, and water savings

Protect Freshness and Boost Profits with FogMist

Choosing the right humidity system is not just about mist. It’s about health, efficiency, and profit. If not cleaned rigorously, ultrasonic humidifiers can increase bacterial concentrations in the air and on surfaces, posing contamination risks. Meanwhile, targeted humidity control, such as FogMist, has been shown to safely and efficiently reduce produce shrinkage by up to 50%. Ready to keep your fresh food fresher, without the risk of contamination? Contact our Prodew experts today.

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