Another area of focus on all types of equipment, including conveyors, is metal finishes. Some metals have microbial coatings. Others have finishes, like the No. 4 stainless steel finish that has short, parallel finishing lines and “looks pretty.” But Monaweck contends that those lines are like scratches that microbes can attach to. “We don’t use it on food-contact surfaces,” he says. “I think in the 21st century we will get away from finishes like No. 4 on the food-contact surface because of the chance of microbes attaching to the finish.” Microbes are less likely to attach to a mirror finish, but he says that’s too expensive to use in the food industry, so there are other smooth finishing alternatives.
You Might Also Like
Explore This IssueOctober/November 2013
Also By This Author
Monaweck notes that part of his work is to educate clients about what surfaces work best for their applications. Since more companies are cutting their engineering staff in recent years, it’s more important than ever to educate those staff members who have taken on new responsibilities when it comes to plant sanitation.
Keeping Components Clean
Rollers and drum motors are components of conveyors that also have drawn attention as areas for new hygienic designs. For example, Interroll, a Wilmington, N.C., maker of conveyor rollers and drum motors, has a drum motor design in which the motor, gearbox, and bearings are internal to the tube, improving its hygienic value, comments Tom Dickinson, product manager. He says the company’s products, known as AC Drum motors, have an Ingress Protection Rating of IP-66, meaning they can be washed down at high pressure and protect against particles. In addition, lubrication is done internally using food-grade oil that he says is approved by the FDA.
According to Dickinson, there’s anecdotal information from customers who feel the press-on fit stainless end caps, stainless drum, and stainless surface help eliminate crevices where bacteria can build, and are quicker to clean. “Some believe the reduced bacteria makes the conveyor a more hygienic design, thus reducing the chances of recall due to bacteria spreading on food being conveyed,” he notes. He says the average price of a recall is $20 million to $30 million, so the penalty for not minimizing bacteria is high.
“The challenges have to deal with the spread of bacteria and the methods in washing down a conveyor or system,” Dickinson points out. “Bacteria travel with water.” Interroll motors, he says, have fewer crevices for food to get trapped compared to external gear motors, and if food does get stuck, it can be washed away more easily. Both the end cap that holds the drum motor in place and the drum motor itself were designed with hygiene in mind, he says.
And like the Walker Custom conveyor belt, the Interroll drum motor can be cleaned in less time, in this case one third of the time, so there’s a production cost savings, Dickinson says. Stopping a line for cleaning can mean $60,000 to $70,000 per minute in production, he notes. “Even a fraction of a minute is a big deal.”
Jake Hughes, sales manager for Omega Metalcraft Inc., Suffolk, Va., who is a customer of Interroll, says the internal nature of the drum motor is good for his end users. He builds conveyers for the ready-to-eat environment. “Most conveyors in the field use ball bearings that require grease,” he explains. “But these [Interroll] have a motor and gear box that are sealed, so there’s no harborage points and nothing is exposed to the elements.” According to Hughes, most Listeria is found in food-grade grease that is used to lubricate bearings, and some plants have grease systems that self-lubricate the bearings. He says a prominent poultry processor based in North Carolina uses the sealed drum motors to avoid such grease problems, which have been tied to recalls in the past. The drums, he notes, eliminate most of the crevices and harboring points.