Lubricants perform a huge variety of roles in machinery, mostly as a means to reduce friction between moving parts. And there are many opportunities for lubricants to come into contact with food and food packaging in most food handling systems.
Lubricants are also placed deliberately in contact with food, as in the case of release agents used to prevent food sticking to grills or baking pans.
Lubricants are most often liquids, but they can also be non-liquids, such as grease, paste and powders. They typically contain 90% base oil and 10% additives. The additives deliver performance characteristics such as increased viscosity, resistance to corrosion or resistance to oxidation.
The base oils in lubricants are usually mineral oils derived from crude oil. These may be designated as synthetic or non-synthetic. Generally speaking, non synthetic oils are derived from crude oil by solvent extraction and by hydro-cracking, whereas synthetic oils are manufactured from crude oil by processes such as isohydromerisation or other chemical reactions.
Base oils from animal and plant sources are also used to create lubricants. Canola, castor and palm oil are commonly used plant products, and are often used to create specialist synthetic esters. Tall oil, from animal sources and lanolin from sheep’s wool grease are also used as components of lubricants.
Solid lubricants include Teflon (PTFE), graphite and other inorganic solids, such as boron nitride, molybdenum disulfide and metal alloys of lead, tin and zinc.
Food grade lubricants
HACCP-based food safety systems require lubricants that could come into contact with food to be ‘safe’. Lubricants that are designed to be safe for use in food processing are commonly marketed as ‘Food Grade’. Food grade lubricants have a low level of toxicity and are usually formulated to be a pale or clear colour and have a low odour.
There are of course many characteristics of lubricants that affect the choices of the food industry; viscosity, performance and cost all being important. Operational tolerances must also be considered, since heat, steam and acidic environments are common in the food industry. Food grade lubricants must meet all these requirements, as well as having a suitably ‘safe’ composition.
Many common lubricant additives are moderately toxic and these additives are not suitable for use in food grade lubricants. With respect to ingredients and formulation that are considered safe, the lubricant industry usually makes reference to the US FDA 21 CFR (Food and Drug Administration Code of Federal Regulations 21).
To claim ‘Food Grade’ status for their lubricants, manufacturers may declare compliance with the FDA requirements or with ISO or European standards for food grade lubricants. Many manufacturers register their products with NSF – a US-based non-government safety and hygiene organisation. The NSF registration category system is used for lubricants for ‘incidental food contact’ – designated H1 or for direct food contact – designated H3. There is also a category, H2, for lubricants that are suitable for use in food processing areas where there is no possibility of the lubricant or lubricated part contacting food.
NSF registration is based on a formulation review and a review of labels and instructions for use.
Background check
A significant weakness of the system is that it does not include an assessment of the manufacturing systems of the lubricant manufacturer.
With a focus on formulation as a means to designate a lubricant ‘food grade’, it is easy to overlook the necessity to manufacture, pack and store lubricants so that they are hygienic and free from contamination, which could lead to hazards in the food that they may contact.
Lubricant manufacturing systems should address the need to prevent chemical contamination by toxic substances, which could occur from errors during batching, blending or labelling processes or by inadvertent contamination of raw materials or packaging materials. Protection from biological hazards, such as might occur if rodents or insects made their way into empty packaging containers before filling, is equally important.
Labels and marketing materials for food grade lubricants list declarations of conformance and certifications for the product. NSF, AQIS and some other certifications are based on formulation, instructions and labelling alone. Other certifications, including certification to ISO 21469:2006, and HACCP Australia Standards, also take into account the manufacturing systems of the lubricant suppliers to ensure that the product has been manufactured and packaged hygienically and safely.