Processing

Food-grade lubricants come of age

Past trade-offs between performance and safety have disappeared

March 7, 2012
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Food production consists of a vast array of equipment—pumps, mixers, oven chain drives, tanks, pipes, conveyor systems, compressors, automatic doors and many other units and systems. All of it needs to be lubricated properly to keep working. Plant managers know different machines require different lubricant solutions and that stocking, tracking and deploying lubricants effectively are critical to plant performance.

On one side, it’s about mechanics. Parts must move freely and be protected from friction, wear, corrosion, rust, deposits and all the other effects caused by an industrial process. Lubricants must ensure good pumpability, temperature stability (both high and low), oxidation resistance and washdown performance, as well as long replacement cycles and other factors.

On the other side, it’s about food safety. Lubrication programs in food manufacturing have to go the extra distance to ensure the safety and well-being of consumers, in addition to complying with government guidelines. Recently, a number of highly visible recalls and, in some cases, tragic food safety failures, such as melamine poisoning of milk in China and Listeria in packaged meat in Canada, have spurred increased interest in raising the food safety bar, including the choice and deployment of lubricants.

In the 1960s, USDA established three classes of lubricants used in food production applications: H1 (classified as food-grade and approved for incidental contact with food), H2 and H3. In 1998, certification responsibility transferred to the National Sanitation Foundation (now NSF International).

The limit for incidental contact for H1 lubricants remains 10 parts per million. These lubes have highly refined synthetic, mineral and vegetable bases. They can contain only approved base stocks, additives and thickeners (if grease), based on FDA Guideline Code of Federal Regulation (CFR) 21 178.3750.

H2 lubes are classified as having no possibility of contacting food. For this reason, they are not limited to a list of approved components. They still must be free of heavy metals, carcinogens, mutagens (chemicals that affect DNA), teratogens (chemicals that cause birth defects) and mineral acids.

H3 lubricants are essentially edible oils that are applied to hooks, trolleys and similar equipment to prevent rust and corrosion.

H1 lubricants are often referred to as “above the line” lubricants—used on equipment or mechanical components where there is the possibility they may drip onto the food production line below and cause incidental contact. H2 and H3 lubes, on the other hand, are often referred to as “below the line,” where there is little or no chance of the lubricant being sprayed or splashed onto the food line above.

Surprises, however, can and do occur. Once in a while, an interruption or event may happen, causing H2 or H3 lubricants to come into contact with food. This is why many processors use H1 lubricants throughout their facilities.

The challenge

Of the three types, H1 lubes are the most expensive because they are the most refined, but the added cost is miniscule in the event of a conventional spill or splash that could potentially shut down a production line or even result in a product recall.

In 1998, almost 500,000 pounds of smoked ham were recalled because of gear oil contact. In 2002, a US-based soft drink producer recalled over 3,000 cases of product that contained gear lubricant. Meanwhile, a Danish milk powder manufacturer recalled 1,100 tons of product that was contaminated by lubricant leaking through a worn axle in a gearbox. And the list goes on.

Switching to 100 percent H1 throughout a plant can eliminate such risk. But until recently, switching hasn’t been so easy. “When food-grade lubes were first introduced in the 1960s, they lacked a number of performance elements that made them unsuitable for certain mechanical demands,” says Jim Girard, vice president and chief marketing officer at Lubriplate in Newark, NJ. “Recent advancements, however, have made H1 products equal to or better than their non-food-grade counterparts. In fact, our finest-performing mineral-based hydraulic fluids at Lubriplate are also food-grade certified.”

Unlike conventional lubricants, H1 products are not potential chemical hazards and thus don’t require a HACCP program. Consequently they provide a much wider margin of food safety and worry-free production. For these and other reasons, many argue they’re not only safer, but more economical in the long run.

Synthetics gaining ground

Today’s incidental food-contact H1 lubricants are made with high-performance “white” mineral oils, either USP (which is the purest) or technical white vegetable oils and synthetic base oils such as polyalphaolefins (PAOs), polyalkylene glycols (PAGs) and esters. These highly refined base oils, coupled with new H1-additive packages, can deliver premium performance.

Tyler Housel, lubricants business director at Inolex in Philadelphia, PA, recently published a white paper on esters. In it, he explains that esters—the basic building blocks of all ester-based synthetic lubricants—are made by reacting an acid with alcohol, and that an endless variety of esters can be manufactured. By combining an NSF HX-1 ester with HX-1 additives, the lubricant can be approved for incidental food contact (NSF category H1). By choosing the ester and additives wisely, the lubricant can be engineered to provide any production and performance characteristics a producer desires.

“If you can use a natural ester, such as a vegetable oil, and it works for you, I’d never tell you to switch,” says Housel. “But natural esters have a limited temperature range, meaning at temperatures above 200°F they can create sludge, gum, smoke, off-odors and deposits. The advantage, of course, is if edible vegetable oil falls on your food product, the food is still perfectly edible. In some cases, however, it is important to note that even vegetable-based lubricants may be inedible because of the additives. Food-grade NSF H1 lubricants are approved for incidental contact and not direct, intentional content.”

But in cooking applications, especially baking, temperatures inside the oven can reach 500°F or more, so natural esters won’t work as lubricants for the conveyor drive chains. The same holds true for low-temperature environments, such as coolers and freezers. “The wrong lube will cause equipment to chatter, squeal, freeze up or wear out, and the line to eventually break down,” says Housel. “Synthetic NSF H1 lubes, however, will stay the course and actually save money over the long term by increasing lubrication intervals by up to five times.” Not having to change lubes as often reduces the chance of contamination and results in less waste.

H1 vegetable oils

Some companies manufacturing vegetable-based lubes are pushing the envelope. Plews & Edelman of Dixon, IL manufactures bio-based H1 UltraLube oils and greases. “With our products, you’re getting a synthetic level performance, at a petroleum level price,” says Dave Babics, senior product manager, lubrication products.

For instance, the UltraLube family contains an H1 NLGI Grade 2 grease that has a drop point rating of 523°F, which is in the synthetic range. “That’s the point where the grease gets so soft it no longer can function as a thickened lubricant,” says Babics. “In normal production, you want to stay about 100 degrees below that.” On the other end of the scale, this particular oil has a low-temperature rating of 32°F, well above the much colder temperatures synthetic lubricants can endure. The company is currently awaiting NSF approval of a new H1 grease with a temperature range between -30°F and 350°F, specifically for cold environments and automatic lubrication systems.

Bio-based lubricants can also leave a thin layer of film on interior metal surfaces once the machine has been turned off. This reduces wear during the next start-up. UltraLube vegetable oil lubricants have been given the USDA’s BioPreferred designation (see www.biopreferred.gov) based on their biodegradability and lack of harsh additives that can cause skin irritation and other problems.

Like vegetable-based oils and greases, ester-based synthetic lubricants form a micro-thin film on the metal surfaces they are in contact with. “The ester fluid film creates a cushion of sorts that reduces friction, saves energy and protects the metal surfaces,” notes Housel.

Summit Industrial Products of Tyler, TX was the first company in North America to be registered by NSF and second in the world to be ISO 21469 certified. Market Manager Ike Texler notes: “Synthetics are the epitome of what you want in a lubricant. They provide the longest intervals between service and the best wear protection.”

Not all that glitters is gold, notes Jim Girard. “A thing to watch out for is the many lubes claiming to be 100 percent food-grade when they’re not.” The best way to be sure is with a letter from the NSF, or CFIA in Canada, stating the product is, in fact, food-grade and a similar letter from the manufacturer which is called “A Letter of Guarantee.” (An approved list of food-grade lubricants is available at www.nsf.org.)

Packaging is another consideration when choosing a lubricant. For instance, the most common container for fluid lubricants in the food industry is the 55-gallon (208-liter) steel drum. “Make sure your supplier is using new drums and not refurbished ones,” says Girard. “The simple reason is purity. Used drums create a greater risk of contamination depending on who used them last.”

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