Lubricants and heat transfer liquids

Lubricants reduce friction in mechanical machine parts and are therefore maily used in food processing equipment to provide protection against wear, but also against corrosion and oxidation (rust) and in some cases are even provide a sealing effect. They are also sometimes used to dissipate heat (cooling) and transfer power. These lubricants must be compatible with the rubber and other sealing materials used in food processing equipment, and be of food-grade quality to prevent harmful contamination of food products.

Lubricants can be in the form of oils or greases.

Oils are usually found in gear transmissions, engines, hydraulic as well as pneumatic systems, and central lubrication systems, Oils are also sometimes used as heat transmission liquid in heat exchangers.

Greases on the other hand, are used in bearings and valves. They are lubricating oils that have a thickening agent added to the formulation.

Case study:

In 1998, more than 490,000 pounds of smoked boneless hams were recalled by Smithfield Foods because they were contaminated by a gear lubricant after several customers reported a “bad taste” and “burning in the throat for up to three hours” from eating the ham. 

This is just one of a number of examples, where food was contaminated by a lubricant that seaped out from the food processing equipment. Therefore, maintenance of seals, gearboxes, valves, pumps, and moving parts is crucial in food processing, as is the use of foodgrade lubricants, which are safe to ingest, odor-, taste- and colorless. Foodgrade lubricants must also be resistant to degradation when in contact with food products, certain process or cleaning chemicals, hot water or steam, and must not become contaminated by bacteria.

Food-grade lubricants are put into categories based on the likelihood they will contact food:

H1 lubricants are food-grade lubricants used in food processing environments where there is some possibility of incidental food contact.

H2 lubricants are lubricants used on equipment and machine parts in locations where there is no possibility that the lubricant or lubricated surface contacts food.

H3 lubricants, also known as soluble or edible oil, are used to clean and prevent rust on hooks, trolleys and similar equipment.

Image source: https://www.bakeryandsnacks.com