There is also added pressure from stricter regulations regarding food quality and factory cleanliness. And hanging over all is the increased potential for unwelcome media coverage should some type of incident ever result from poor maintenance practices. Negative publicity could have the worst long-term effects on a companys continued profitability.

All of these things contribute to rising demand for food-grade lubricants – both for new and existing equipment. Oil and grease marketers are jostling to meet this demand, with new companies entering the market while those already present increase their product offerings. It would be a lot for buyers or plant engineers to absorb even if identifying a replacement lubricant was a simple process. In fact, the process can be very complicated, and plant operators need to consider numerous factors to ensure they make a good choice.

Food-grade lubricants are manufactured out of recognition that they might, however accidentally, have some contact with the foods and beverages that processors are making. As a result, they must be non-toxic and have neither taste nor smell. Processors generally have discretion to choose if and where to use them. One thing operators should consider is that not every piece of equipment needs a food-grade lubricant. When deciding whether to use conventional products, a processing company may want to seek independent advice , as the lubricant supplier may have a vested interest in encouraging a switch to more expensive food-grade products.

Where an operator does opt for food-grade lubricants, they may find less choice than they normally expect. Other major industries can find lubricants that are made specifically for most any type of machine or application. The same is not true for food-grade lubes, and so operators often must find the product that is the closest fit, which may warrant experienced assessment.

It is not uncommon to come across a food processing plant where every electric motor is lubed with a single grease – perhaps a non-food-grade product formulated with lithium-based thickeners. Those motors might also be on the same re-greasing schedule. In fact, in order to simplify maintenance routines, they might even be greased on the same schedule as bearings in equipment other than motors, regardless of the type of motor or operational parameters.

Such practices may in some instances lead to over-greasing, which could potentially damage the motor. The author has studied many such plants and frequently sees equipment failures where greasing practices could be recognized as a cause. One should never forget that unplanned down-time due to machinery failure is very costly indeed, so it is important to choose lubricants and to follow maintenance practices that are appropriate for each machine.

One of the most common reasons for using food-grade lubes is exposed food or beverages passing under lubricated equipment, thereby posing the possibility of leaked or thrown lubes falling onto the food. Such configurations are especially common in older plants where growth created a need for expansion but where sites did not accommodate an enlarged production footprint. Unable to spread, operators expanded vertically, leading to situations where conveyors pass above and underneath each other. In such cases, the need for food-grade lubricants is usually obvious, even in electric motor bearings.

Will the selected food-grade grease be as good as its non-food grade counterpart in this particular application? Maybe not, though it must be said that polyurea-based greases perform very well in this application, and they do come in food-grade varieties. Whichever product is selected, re-greasing frequencies will have to be reexamined and probably altered.

When a plant switches from a non-food-grade to a food-grade lubricant, it needs to consider the compatibility of the two products, particularly so with greases, or be careful to completely flush the old lubricant. Operators also need to consider possible changes in the viscosity-temperature relationship. Suppose one was to replace a conventional oil that had an ISO viscosity classification of 320. The natural tendency might be to choose a food-grade lubricant with the same viscosity.

However, most food-grade oils have a higher viscosity index than their corresponding conventional counterparts. In this example both would have viscosities of approximately 320 centiStokes at 40 degrees C, but the food-grade oil would have a lower viscosity at extremely low temperatures and a higher viscosity at high heat. Consequently, a replacement oil may need to be of a higher ISO classification if used in a freezer or of a lower grade for a baking application. Obtaining the correct viscosity is important because it can affect wear rates in geared units, power consumed in electric motors and performance of hydraulic systems.

Of course, the most critical aspect of a food-grade lubricant is that it needs to be non-toxic and unnoticeable in case it does come into contact with food. Fortunately, operators can find lists of products verified for meeting these requirements. Industry recognizes three primary categories of food-grade lubes – H1, H2 and H3 – originally defined by the United States Department of Agriculture as part of its former program to identify non-food compounds that were safe to use in food processing plants. The largest category – H1 – was for lubricants used in applications where it was possible for the lube to have incidental contact with the food or beverage. H2 was for lubricants used in applications where there was no possibility of incidental contact. H3 was for edible oils used in applications such as spraying on hooks to prevent rust.

For many years the USDA also published a list of products – known as the White Book – that met the criteria of each category, but the agency stopped doing that in 2000. An American company, NSF, revived the program, and subsequently added a plant certification component. In 2008, a European firm, InS Services, began offering its own registration program, likewise identifying lubricants that conform to ingredient criteria set by the U.S. Food and Drug Administrations 21CFR Section 178.3570. At this time, InS does not certify plants for adhering to production quality and cleanliness standards, but its credibility for checking formulations is no less than NSFs.

Some food and beverage companies decide that they are unwilling to risk the chance of a mix-up during lubricant handling and a non-food-grade product being installed where a food-grade product is intended. These companies eliminate the possibility altogether by switching their entire plant to food-grade products, even applications which on their own would not require them. They take this simpler approach even though it costs a bit more to go wholly food-grade.

In another way, however, such a strategy may complicate the selection of specific lubricants. The fact that food-grade products come in fewer varieties means it is less likely operators will find lubes formulated specifically for particular applications. In such cases they will have to look for the closest available match – an exercise that requires much more analysis.

It is important to recognize that performance properties of food-grade lubes can vary considerably, even among those that fall into the same H category. For example, an operator may come across two H1 greases, one formulated with an aluminum complex thickener and a white oil base stock, the other with calcium sulfonate complex thickener and synthetic hydrocarbon oil. These products may have identical NLGI (2) consistency, but they will exhibit quite different characteristics due to their chemical differences. An aluminum complex grease is inherently quite tacky, which may not be suitable for every application, whereas a calcium sulfonate complex products exhibit very good extreme pressure properties, good water resistance and can operate across a wide range of temperature. Obviously the operators choice will depend on which of these properties is suitable for a particular application.

The food and beverage industry often uses food-grade hydraulic oils due to the high pressures encountered in hydraulic systems. If leaks develop or pipes burst, fluid will likely be sprayed over a large area, so the possibility of incidental contact by hydraulic oil is often greater than for other lubricants.

There will also be instances where it appears that a food-grade lubricant needs to be used but it is not practical to do so. Consider, for example, chain drives passing through an oven. Some of these ovens operate at very high temperatures, convey the food quite slowly and of course are enclosed. The author has seen cases where operators conducted trials of several food-grade products but found them inferior to non-food-grade products already in use.

In one instance, the oven was configured such that the lubricant could only be applied at one point on the chain, thereby requiring that it have unsurpassed adhesion and especially low volatility in order to lubricate the linkages and pins of the chain adequately for one complete cycle. None of the trialed food-grade products could match the incumbent, and yet it was deemed that incidental contact between lubricant and food was possible, so the application needed a food-grade product. In the end, the operator re-engineered its equipment to ease the challenge on the lubricant. Such solutions create additional cost, of course, but are not uncommon in the industry.

The range of food-grade oils, greases and pastes seems to be continually increasing, and there are food-grade products to provide adequate performance for more and more applications. It makes sense, therefore, for food and beverage processors to continue making greater use of these products. But that doesnt mean that the process of selecting a replacement is straightforward. Often is it not, and operators need to carefully consider a number of factors to ensure they pick a product that will adequately protect their equipment.