New Antimicrobial Treatments Are Enhancing Food Safety in the Plant

Chemical treatments that sound innocuous or don’t have to be listed on labels are becoming common, but precision application is a must for effectiveness and cost control.

By Kevin T. Higgins, Managing Editor

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Chemicals that don’t sound scary on a label or are processing aids exempt from label disclosure are in high demand for combating bacteria and other food contaminants, and that’s stimulating considerable R&D work in the supplier community.

Those clean-label interventions usually command a premium price, so delivery systems that don’t overdose but still deliver a knock-out punch also are in high demand. Rarely is the supplier of the anti-microbial and the delivery system one and the same, however, leaving it up to food companies to prove they are able to deliver a consistent and effective dose of prevention.

An exception to the rule is electrochemically activated water (ECA), also known as electrolyzed oxidative water. By combining purified water and sodium chloride (salt) in an electrolytic generator, a chemical reaction creates two fluid streams of sodium chloride, an effective cleaner, and hypochlorous acid, a powerful oxidizer. The chemicals are relatively benign and don’t require users to wear protective gear.

ECA had its roots in Soviet R&D in the 1970s, and the Japanese embraced it as an inexpensive alternative to chemicals for carpet cleaning, but it wasn’t until the turn of the century that the technology started to take root in North America. Often positioned as a green alternative to chemical cleaners and sanitizers, ECA can lower operating costs and is believed to be effective against viruses, an advantage that is attracting interest from hatcheries and chicken and turkey growers concerned about avian influenza.

Beverage bottlers also are beginning to adopt ECA, though the technology has appeal in all food-grade cleaning and sanitizing applications. The sanitizer has been used in direct contact with meat and poultry, though FDA sets a 50ppm limit for free active chlorine, points out Peter Bramsen, project manager-Klarion at Spraying Systems Co., Wheaton, Ill. However, active proteins in the sanitizer can have a negative impact on meat. Bramsen advocates using the solution on food-contact surfaces, where concentrations up to 200 ppm are permitted.

Precision spray nozzles are Spraying Systems’ forte, but several years ago the firm acquired an Indiana firm that had developed an ECA system for commercial use. Engineers refined the cell design of the reactor and developed an industrial scale unit, which was dubbed Klarion. Because both the alkaline cleaner and acidic rinse are generated simultaneously, storage of one or both solutions is necessary. Some manufacturers employ a mobile cart outfitted with two buffer tanks; if the tanks are closed, the solutions remain stable up to 60 days. If left open, the solutions quickly dissipate.

Juiced water

ECA isn’t the only alternative chemistry based on electrolysis. Adding an electric charge to a fluid can give it magnetism much stronger than gravity, turning a unidirectional spray into an omnidirectional mist. If disinfectant or cleaning chemicals are included in the fluid, the result is a significant reduction in chemical use.

Electrostatic sprays have been used effectively for painting automotive vehicles for decades. A quarter of a century ago, a University of Georgia agricultural engineer decided to apply the concept to farming, first for crop applications and more recently on poultry trucks as part of the avian influenza counteroffensive.

Table grapes, papaya and other high-value crops were among the first food applications. The magnetic force of the sprayed droplets proved particularly well suited for dispensing mold inhibitors onto cantaloupes and other produce with nooks and crannies, according to Bruce Whiting, president and owner of Electrostatic Spraying Systems, Watkinsville, Ga. Reasoning that “the same thing works for food products as it does on plants out in the field,” Whiting is migrating the technology to food production, both for surface cleaning and direct food contact.

In Whiting’s system, a liquid stream is mixed with air in an atomization zone, where a small electrode applies a charge (usually negative). The resulting droplets, typically in the 30-40 micron range, are blown toward a target but are able to turn and pivot, defying gravity as they seek grounding on the target.

“We say we save 25 percent on chemical use, though some clients report savings of 50 percent or more,” he says. As much as 80 percent less water is used, an important factor in reducing drying time between sanitation and line start-up.

ESS was a first-time exhibitor at January’s International Production & Processing Expo (IPPE) in Atlanta, where the firm showcased a 30-lb. backpack unit that can mist surfaces for two-plus hours before recharging. In a technical presentation, Whiting told attendees Tyson was testing the technology for beef carcass spraying, although it’s up to the processor to demonstrate the efficacy of the antimicrobial treatment.

The same prove-it requirement applies to ultrasonic spray coating of whole muscle and slices of deli meat. Companies like Spraying Systems and Sono-Tek Corp. work closely with vendors of antimicrobial treatments, but it is up to suppliers such as A&B Ingredients and phage developer Micreos, working closely with processors, to demonstrate the reliability and consistency of an application in a specific plant’s process.

The maxim "better safe than sorry" is food safety’s rule of thumb, and many products are overcooked or overdosed to ensure safety. But the combination of a clean-label focus and the high cost of new treatment options is putting a premium on precision when applying antimicrobials.

Joseph Riemer, vice president-food business development at Milton, N.Y.-based Sono-Tek, cites the example of lauric arginate, a saturated fatty acid with bactericidal properties. If dosing is below 50ppm, it qualifies as a processing aid and doesn’t require label disclosure.

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