Systems evolve to produce safe processed food

April 13, 2016

As the market for better-for-you dried produce snacks grows and changes, so does the industry providing the food safety systems and equipment that support it.

A week doesn’t go by that there isn’t a new product rollout: broccoli crisps, mango slices and the like. Other staples like cranberries and raisins are enjoying their place in the sun, so to speak, as snacks and ingredients.

The safety technology and processes behind this burgeoning industry also continue to evolve as manufacturers work to meet the needs of processors, who are continually refining processes tailored to specific products and conditions.

“Our customers are interested in processing vegetables, beans, pulses and leafy products, and dehydrated fruits, in addition to the consistent infused products and typical ingredients,” said Dave Reynolds, area sales manager for Buhler Aeroglide in North Carolina. “Many of these vegetables are being used for ingredients and nutraceuticals.”

As a result, Buhler offers a range of sanitation-focused dryers, dehydrators and roasters for fruits that include blueberries, cranberrries, cherries, raisins, apples, apricots and coconut. Vegetable applications include onions, broccoli, potato products, carrots, peppers, mushrooms, alfalfa and spices like cilantro, parsley and garlic.

The Buhler Aeroglide hygienically-designed dryer used for dried produce food products. Photos: Buhler Aeroglide
The Buhler Aeroglide hygienically-designed dryer used for dried produce food products. Photos: Buhler Aeroglide

The company also offers analytical lab testing, with an on-staff food technologist available to work with customers to develop the most efficient thermal processes for the products they want to introduce, said Buhler Aeroglide Vice President of Process Engineering Tom Barber.

“More and more … manufacturers are asking for new kinds of support, including help with hazard analysis and critical control point plans that are required by the Food Safety Modernization Act for certifications,” Barber said.

Process matters

When it comes to food safety, a common denominator for products in this category is moisture.

“Fruit and other fresh produce are high-moisture products that make material handling challenging and delicate,” said Reynolds. “High- moisture foods are the most challenging due to delicate material handling requirements and the degree of continuous cleaning that’s required to ensure hygienic standards.”

When customers bring new products to the market, Buhler Aeroglide works with them to develop processes to achieve the results they’re looking for.

“A multi-stage process works well for fruits and vegetables,” Reynolds said. “In the case of sugar-infused cranberries, the product becomes sticky and clumpy and must be re-oriented to ensure precise drying.”

Darryl Hastings, Oregon-based national sales manager for Commercial Dehydrator, said the dehydration process must be adapted to each product.

“It is the dehydration process that kills the bacteria in the product if done properly,” he said.

There are three parts to his equation: temperature, humidity and time. The jerky industry was a forerunner in perfecting this process, Hastings explains, adding that the right balance of those three factors is essential for killing bacteria in the product.

“If we don’t have the humidity, the bacteria can live through that drying process,” Hastings said. “They’ll encapsulate themselves in a little envelope and can live through that process, so when exposed to water again, they can come alive (and become) viable, reproducing bacteria again.”

His company offers an enclosed system that allows humidity to build to a certain point, at which time the air is expelled and fresh air pulled back in.

“If it’s too dry, bacteria can live through that dry air,” Hastings said. “Number two, if it’s too dry, the product gives up water so fast to the surface that it brings salt and stuff that should have stayed inside, out to the surface. If I get that white speck on my pineapple, on my jerky, I know that water came out so fast it brought that salt out with it.

“Water is going to help us kill bacteria, raise the core temperature and jumpstart dehydration.”

Jon Kimble, food safety services manager for the Dried Fruit Association of California, said moisture in the manufacturing environment itself is a safety consideration.

“In a dry area, you need to manage the moisture because you don’t want to have anything recontaminating the product,” he said. “You don’t want to be growing any listeria in the drains or anything like that.”

Beyond that, Kimble said, product contact surfaces are probably the most critical points for sanitation.

The sanitary outfeed of the Buhler Aeroglide dryer.
The sanitary outfeed of the Buhler Aeroglide dryer.

“It’s a pretty straightforward concept — any kind of drying screens or tools or implements are the biggest things to think about and focus on, in terms of controls for sanitation — that and your supply chain,” Kimble said.

Many processes utilize a drying screen of some kind. Residue can linger after a product has been processed, and so the screens must be cleaned before switching to another type of commodity to avoid contamination with unreported allergens, he explains.

“Sulphites are a big concern,” Kimble said. “A lot of stone fruit will be sulphur treated, as well as golden raisins as opposed to traditional raisins.

“We tell people, ‘Don’t get stuff in other stuff.’ If it’s got something in it that it shouldn’t have in it, it’s adulterated.”

Hastings said using liners is also recommended when processors are using one dehydrator for multiple commodities — and many do, when one medium or large dryer can run in the hundreds of thousands of dollars.

“The product goes on the liner instead of on the tray itself,” he said.
Some new formulated and foaming cleaners that are alternatives to a simple caustic cleaner are effective in certain applications, Kimble said. Dry ice cleaning, which is similar to sand blasting except it uses more hygienic dryicegranulesblastedbyairpressure, is another option in some cases.

“It depends on the type of residue,” Kimble said.

Processors should also consider other factors before introducing high- or low-pressure washing.

“In food processing areas, you may not want to do high-pressure washing on floors (which will then) splash on food handling equipment,” Kimble said. “You’ve really got to understand your application of what the best approach is.”

Sanitizing in itself isn’t enough, he adds. It must be followed by verification. “Visual inspection is a huge tool for verification (as are) real-time swabs you can use that give you a quick result in a matter of a few minutes,” he said. Kimble also stresses the importance of employee hygiene programs. Residue from food handled at home or consumed during a break can result in contamination.

“When we wash our hands, we’re not just preventing allergen contamination, we’re removing any pathogens or chemical materials that might be harmful,” he said.

Game changers

Steve Blackowiak, director of food safety and research and development for Buhler Aeroglide, said his company’s collaborations with food manufacturers in recent years have led to advances in food safety research as well as he development of “game-changing hygienic processing equipment.”

The end result: dried apple chips are an example of dried produce food products.
The end result: dried apple chips are an example of dried produce food products.

“We know food processors need to improve uptime, for faster and better cleaning, improved access, and minimized microbial risks, etc.,” he said. “We’re working hard to understand their challenges and we have some very exciting innovations that are resulting.”

The next generation of hygienic equipment addresses cleanability, access, overall hygienic design and microbiological safety, he explains — all aimed at keeping production moving.

“We have over 30 new patents and revolutionary innovations related to weld finish and sloped surfaces, with minimal fasteners that typically collect debris and harbor bacteria, and a revolutionary new patented conveyor system that’s easy to clean and inspect,” he said.

Products range from the AeroDry single-pass conveyor dryer for processing a variety of fruit and vegetable products; multi-stage dryers for dehydrating fruits and vegetables, as well as sugar-infused products that require reorientation and stacking; and AeroDry Impingement Ovens for fast and uniform processing of roasted vegetables.

Commercial Dehydrator’s dehydrators are built of stainless steel and easily washed down. The equipment can also sanitize itself when it’s run through the dehydration process for a certain length of time.

“Our large machines have a graph on them that shows them each batch … that shows it ran well, that there wasn’t a problem with it, that the humidity was a certain level,” said Commercial Dehydrator’s East Coast Regional Sales Manager Coleen Hildebrandt. “Most everybody else who has the smaller dryers, they’ll keep their own records.”

Of course, many processors rely on older equipment as well. Kimble said it’s important for them to make sure it’s well maintained.

“You want equipment designed with food handling and sanitation in mind,” he said. “A lot of the older equipment is not.

“You’ll see a lot of things like painted surfaces — mild steel that rusts very easily — and those things can add additional risk that may be passed on to your product. Make sure it’s well maintained.”

Safety issues in dehydrating produce don’t typically arise from product that’s been sourced from an approved supplier subject to third-party audit and handled appropriately.

“Produce wise, there’s no product that presents a problem,” Hastings said. “It’s the dryer, and the processes are only as good as the operator attending or guiding those processes.”

— Kathy Gibbons, contributing writer

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