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Food grade lubricants

Food grade lubricants are industrial lubricants and they are similar to them in most aspects. Their purpose is to fulfill the same tribological requirements as other lubricants: They must provide protection against friction and wear and transfer power. In short: They keep the machinery running. However, food grade lubricants need to comply with a set of additional specific requirements1.

They need to be:

  • odorless
  • tasteless
  • colorless
  • physiologically inert

Due to their use in food and beverage production they are much more strictly regulated than any other lubricants used in e.g. your car engine, where food safety is not a factor to consider. Food grade lubricants may be used in applications where incidental food contact may potentially occur. Such incidental contact is limited to a trace amount: It must not exceed ten parts per million (i.e. 0.001 percent), or else the food is deemed unsafe for consumption. Using unsafe lubricants can lead to contamination of food, which could lead to resulting in pollution-caused illnesses of customers, leading to a loss of trust in affected food brands and manufacturers.

Food grade lubricants are used in various system parts within production and processing lines, e.g. as gear oils, chain oils, compressor oils, hydraulic oils, or corrosion preventative oils.

Chemistry

Similar to any other formulated lubricant, food grade lubricants consist of base stocks and additives. Depending on their different fields of application, i.e. for which equipment and in which area they are used – for slow or fast running machinery, at high, low, or changing temperatures, under high pressure, under high humidity – lubricants are formulated from different chemical base stocks and additives.

Evolution

At the beginning of industrial food production, plants and output were rather small compared to today. Nowadays, food and beverage production and processing lines as well as pharmaceutical and cosmetic plants usually run seven days a week, 24 hours a day and production speed is increased to the maximum in order to be the most profitable. Downtimes due to breakdowns or repair of machinery are costly and need to be kept to a minimum. Here, using the correct lubricants plays a major role in ensuring food safety and extending the lifetime of machinery and parts to keep repair costs as low as possible.

Early food grade lubricants were based on edible oils and fats, but the limits of these lubricants were soon recognized. Edible oils degrade fast, they tend to solidify at low temperatures, smoke when heated, and polymerize when kept at high temperatures. Machinery requires lubricants providing a higher performance while at the same time being able to withstand severe conditions. Therefore, lubricants of different chemical bases were formulated with additives to fit specific requirements2.

Base materials

  • Mineral oil/white oil
  • Polyalfaolefin (PAO)
  • Esters
  • Polyalkylene glycol (PAG)/polyglycol
  • Silicone oil
  • Perfluoro polyether
  • Edible oils and fats (e.g. lard, soybean oil)

In order to improve the performance of the formulated product, some base materials can be mixed with each other.

Typical additive types

  • Anti-wear additives (friction modifiers, extreme pressure additives)
  • Antioxidants
  • Corrosion inhibitors
  • Viscosity modifiers
  • Pour point depressants
  • Surfactants, dispersants, and emulsifiers
  • Antifoam agents

For greases, additionally a thickener is required. Also here, depending on the chemical base and intended application, the thickener can be based on calcium or aluminum – silicates or PTFE can be used as well.

Viscosity measurement of food grade lubricants

Reasons for viscosity measurement

  • Specific lubricants for specific applications
    Food producers select food grade lubricants according to their specification and the intended application. To ensure reliable and low-wear working of machinery a certain viscosity of the lubricant is required.
  • Reproducible products
    Manufacturers of food grade lubricants must ensure that their products have reproducible properties. So besides lubricant development, also the quality check is important. For food producers, a viscosity check of the incoming lubricant ensures they get the right material in the required quality.
  • Machinery health
    In order to get the highest possible output from the machinery, all relevant parts must be lubricated well to ensure economic and low-wear operation. Contamination like water, dust or debris within the production line also changes the lubricant properties. Wear of the lubricant leads to a lack of lubrication and equipment can be damaged, which leads to cost-intensive downtimes.
  • Requirement of condition monitoring
    Monitoring the in-service lubricant is an essential part of HACCP. The degradation of in-service lubricants due to contamination is also a risk factor regarding health and hygiene (growth of bacteria and other hazardous microorganisms).

Which parameters are determined?

In their product information sheets, some manufacturers state density at 15 °C or at 20 °C, or specific gravity instead of density as well as Saybolt viscosity (SUS) at 100 °F and 210 °F.

For food grade oils, the kinematic viscosity is usually determined for the final product, but also for the base oil. For food grade greases, the kinematic viscosity is determined for the base oil only.

Find examples for the viscosity of selected food grade lubricants in this table.

ISO viscosity classification (ISO 3448)

As they are industrial oils, the kinematic viscosity of food grade lubricants is classified according to the ISO viscosity grades system. A mid-point viscosity for each viscosity grade at 40 °C is stated, the allowed range for the product’s viscosity is a deviation of ±10 % from the mid-point value.

Classification and regulation

Lubricants used for food production and handling are listed by NSF International in category H – nonfood compounds. Release agents are part of the group proprietary compounds and are listed in category 3 – food processing substances. 

Food grade lubricants classification

Class Definition, purpose
H1

Lubricants considered the "true" food grade lubricants or food safe lubricants. They are intended to have incidental food or beverage contact in the production line. All contents of the lubricant (base stock and additives) as well as the maximum levels of the lubricant present in the foodstuff are strictly regulated in FDA 21 CFR 178.3570. They have to be listed on the NSF H1 lubricant list.

HT-1 

Heat transfer fluids in cooling and heating systems where incidental food or beverage contact is possible. They must comply with FDA 21 CFR 178.3570.

HX-1 

Ingredients for the formulation of H1 food grade lubricants. Similar to H1 lubricants, they are listed on the NSF list and are regulated according to FDA 21 CFR 178.3570.

HTX-1

Ingredients for the formulation of HT-1 heat transfer fluids.

H2 

Such lubricants are used for applications in the production line where food contact is not possible. They are not considered real food grade lubricants and they are less strictly regulated than H1 lubricants. 

HT-2

These are heat transfer fluids. But contrary to HT-1 fluids, food contact is not allowed.

HTX-2

Ingredients for the formulation of HT-2 heat transfer fluids.

H3

Soluble oils which are not intended for contact with food. They are, for instance, applied in rust protection for items like hooks or trolleys. Prior to using the equipment, this kind of lubricant must be removed from surfaces getting in contact with edible products. These substances are less strictly regulated than H1 lubricants, too.

3H

Release agents, which are used to prevent food products from sticking on molds, grills, or other equipment. Their maximum level in foodstuff is regulated in FDA 21 CFR 178.3570.

Authorities and regulations

US Food and Drug Administration (FDA) – Codes of Federal Regulation (CFR) in Title 21

  • FDA 21 CFR 178.3570 – Specifies all substances (base stocks and additives) used for formulating H1, HT-1, HX-1, H3 lubricants, which need to comply to this FDA regulation
  • FDA 21.CFR 178.3620 – White mineral oil as a component of non-food articles intended for use in contact with food
  • FDA 21.CFR 172.878 – USP mineral oil for direct contact with food
  • FDA 21 CFR 172.882 – Synthetic isoparaffinic hydrocarbons
  • FDA 21 CFR 172.182 – Lists substances generally recognized as safe3

NSF International (former: National Sanitation Foundation)

Founded in 1944, NFS International is a non-governmental organization well-known in all aspects of food safety. They are one of the world leading organizations for solutions regarding the public health system. NSF International4, 5 lists all approved food grade lubricants and their ingredients for incidental food contact in the production line, i.e. lubricants of the categories H1, HT-1, HX-1 and 3H.

ISO 21469

ISO 21469 shows that a manufacturer’s product meets hygiene requirements for formulation, manufacture, use, and handling throughout its entire life cycle. Using ISO 214696 certified lubricants can help processors reduce their risk of contamination. Like product registration, this certification ensures lubricant ingredients are safe in the event of incidental food contact.

ISO 22000

ISO 220007 is a food safety management certification system for food manufacturing recognized by the Global Food Safety Initiative. It is intended to be used by food producers, not for suppliers of equipment, lubricants, and service parts.

HACCP – Hazard Analysis of Critical Control Points

HACCP is a methodology for defining and controlling present or potential hazards in food production. In order to ensure safe processing procedures, this hazard analysis should always be performed for new production lines or in case changes in the production line, such as changing the lubricant, occur.

HACCP8 is the dominant and science-based method to ensure hygienic food production. It is accepted worldwide by food manufacturers and food safety agencies including the WHO (World Health Organization) and the FAO (Food and Agricultural Organization of the United Nations) as well as by many governments.

Other regulative organizations

USDA (United States Department of Agriculture):
Initially, this organization administered the registration program for food grade lubricants. They reviewed and authorized lubricants for use in food processing until 1999. Since then, responsibility for the registration program has been transferred to NSF. USDA9 is still a food safety agency as they transact warnings regarding contaminated food products, for example.

CFIA (Canadian Food Inspection Agency):
This organization focuses on a healthy and sustainable animal and plant resource base. They have issued several standards and regulations regarding food safety.

Regulations of religious groups

More and more also the requirements of religious groups are taken into account, for example for lubricants required to produce "kosher" and "halal" food. Certification agencies for kosher food are e.g. OK Laboratories or K-Star. For halal food this is e.g. the Halal Certification Authority (HCA).

EHEDG – European Hygienic Engineering & Design Group; Document 23

This is a non-profit consortium of research institutes and universities, machinery manufacturers, food producers, suppliers to the food industry, universities, public health authorities, and governmental organizations. Document 23 describes best practices for producers on how to use lubricants and on how to avoid or at least how to limit contamination.

Conclusion

Food grade lubricants are one of the most critical substances in food processing and handling for both food safety and machinery health. Selecting lubricants with the right viscosity for the equipment of the production line ensures cost-effective low-wear operation. Monitoring the in-service lubricant is required by HACCP and enables food producers to get out the most value of their equipment. Selecting a lubricant with unsuitable viscosity can lead to premature wear and costly downtimes of machinery. More resources on viscosity determination in general and viscosity determination of lubricants can be found here:

References

1. Gebarin, S. The Basics of Food-grade Lubricants [Online]. Noria Corporation. Available at: https://www.machinerylubrication.com/Read/1857/foodgradelubricantsbasics (Accessed 24 April 2019)

2. Klüber Lubrication Food Industry. Speciality lubricants for the food-processing industry, Speciality lubricants for the bakery industry, Speciality lubricants for the beverage industry [Online]. Available at: https://www.klueber.com/en/applications/industry/food-industry/ (Accessed 24 April 2019)

3. US Food and Drug Administration (FDA). Part 178 Indirect Food Additives: Adjuvants, Production Aids And Sanitizers [Online]. Available at: https://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfcfr/CFRSearch.cfm?CFRPart=178 (Accessed 24 April 2019)

4. NSF International. Quick Reference Guide to Categories [Online]. Available at: http://info.nsf.org/USDA/categories.html#H1 (Accessed 24 April 2019)

5. NSF International. NSF-Registered Proprietary Substances and Nonfood Compounds [Online]. Available at: http://info.nsf.org/USDA/Listings.asp (Accessed 24 April 2019)

6. ISO-International Organization for Standardization. ISO 21469:2006 Safety of machinery – Lubricants with incidental product contact  Hygiene requirements [Online]. Available at: https://www.iso.org/standard/35884.html (Accessed 24 April 2019)

7. ISO-International Organization for Standardization. ISO 22000 Food safety management [Online]. Available at: https://www.iso.org/iso-22000-food-safety-management.html (Accessed 24 April 2019)

8. Vinca, LLC. HACCP for Food Safety Certification Programs [Online]. Available at: https://www.22000-tools.com/haccp-certification.html (Accessed 24 April 2019)

9. U.S. Department of Agriculture (USDA). Health and Safety [Online]. Available at: https://www.usda.gov/topics/health-and-safety (Accessed 02 May 2019)