How to Eliminate Biofilms
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THE MAGAZINE DEVOTED TO NICKEL AND ITS APPLICATIONS |
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STAINLESS STEEL is an ideal material for food conveyor belts because it resists scratching,
denying bacteria a foothold. |
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OPEN-MESH STAINLESS STEEL belts are typically made of S30200, S30400 or S31600 in high-temperature, more
corrosive applications. |
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IN MOST APPLICATIONS food processors do not have to go to the additional time and expense of
removing a belt from the production line for cleaning. |
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WIRE BELT COMPANY OF America produces more then 4,500 belt configurations, with mesh sizes of 50 to 400
millimetres (mm) wide and pitches (the spaces between rows of wire) ranging from as little as 1.5 mm to 20
mm. |
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IF A FOOD BELT is to be subjected to high temperatures or contact with corrosive materials,
S31600 stainless is used because of its additional strength and durability. |
Biofilms are less of a problem with stainless steel conveyor belts. By Dean Jobb
Nickel Magazine, November 2004 -- The next time you order chicken nuggets at a fast-food restaurant, think stainless steel. Chances are your meal has been breaded and pre-cooked on a conveyor belt manufactured by a New England company that specializes in food-industry production lines.
"Anything in a mass-production environment that has been coated, breaded or battered, and then cooked, has probably been on our conveyor belts," says Richard Spiak, vice-president of sales and marketing for Wire Belt Co. of America.
The leading supplier of open-mesh stainless steel belts, Wire Belt uses S30200 and S30400 stainless steel for its conveyors and the more machinable S30300 grade for sprockets and drive components. If the belt is to be subjected to high temperatures or contact with corrosive materials, the company opts for S31600 stainless because of its additional strength and durability.
"We choose those materials because they’re easy to clean and sanitize, and they give us a great deal of strength and flexibility in the applications," Spiak explains. "You’re looking at some demanding environments for these belts."
Bread coatings are highly abrasive. Temperatures inside bulk fryers and ovens may reach 200°C. The overriding challenge, though, is cleanliness. Belts must be kept free from food particles and bacteria in order to meet the rigid standards of government and industry. A major concern within the fast-food industry is eliminating biofilms, a tough layer of bacteria that builds up on the surface of food-handling equipment, much like plaque on teeth.
Stainless steel belts resist scratching, deny bacteria a foothold, and in most applications processors do not have to go to the additional time and expense of removing the belt from the production line for cleaning, says Spiak.
High-density polyethylene plastic has emerged as an alternative to stainless steel for food-processing applications that do not involve cooking. But plastic is more prone to scratching and can be tougher to rid of biofilms. Research at London’s South Bank University found that plastic modular belting accumulated 10 to 100 times more bacteria than stainless steel belts.
Wire Belt’s open-mesh design allows for easy cleaning of the belts, improves airflow when individual products need to be heated or cooled, and reduces belt contact when products are coated or cleaned. The company produces more then 4,500 belt configurations, with mesh sizes of 50 to 400 millimetres (mm) wide and pitches (the spaces between rows of wire) ranging from as little as 1.5 mm to 20 mm.
Wire Belt also stresses the problem of detecting foreign matter in processed foods. Metal detectors are commonly used in the industry, but expensive and less-reliable X-ray machines are needed to find fragments of plastic from belts and other equipment. The company won an award in 2003 for advertisements that point out that virtually all food-product recalls for "extraneous material" in the U.S. involve plastics. The advertisments ask the question: "What’s your conveyor belt made of?"
The company’s belts have non-food applications, and are used on production lines for soldering and cleaning computer circuit boards and for cleaning coated lenses for eyeglasses. Some textile manufacturers use the belts in dryers and dyeing machines.
Founded in 1947, Wire Belt remains family owned and employs 150 people at its Londonderry, N.H. plant. Plants in Britain and Germany employ another 100. Spiak estimates the company produces several million pounds of stainless steel belting each year.
Dean Jobb is a Wolfville, Nova Scotia-based freelance writer.
PHOTOS: Wire Belt Co. of America
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Wire Belt Company of America |
