Choosing bearings for food processing – nine health and hygiene considerations
08 Jul 2022

Extracting, filtering, milling, purifying, mincing, liquefying, emulsifying, cooking, pickling, pasteurising, canning, slicing, dicing and drying are some of the many physical and chemical means through which raw food ingredients are transformed into other forms. 

As with any equipment in a food processing plant, instruments and apparatus need to be assessed on the basis of their longevity, cost and whether they are fit-for-purpose. Important in a hygiene-critical environment though is whether the equipment is safe and hygienic to use. The health toll on consumers can be high if this is not considered, and the impact on a food company can be devastating if hygiene-related issues result in costly food recalls and significant reputational damage. 

As with any food-processing equipment, bearings need to be assessed for their suitability in a given application. Like other apparatus connected with the industry, health and hygiene are important considerations. After all, the often inconspicuous bearing plays a part in many food-related processes. They are intimately involved in blenders and mixers, ice machinery, picking and weighing equipment and conveyors, among other equipment. They perform many millions of cycles and are an essential although often acknowledged part of food processing. As a result, those in the food processing industry might want to look at these seven health and hygiene considerations before they choose a bearing for their production line.

Consider a bearing’s swell index

Fortune Magazine reports that microbiological contamination is responsible for 47% of food recalls. Microorganisms such as bacteria, yeast and fungi, and their build up, should thus be avoided. When it comes to bearings, materials such as non-food-grade nylon should be avoided, since it absorbs water and harvests bacteria. Other bearing materials should be carefully investigated, and only those thermoplastics that do not swell should be considered since trapped stagnant water is an environment in which microbes thrive. 

Choose the right colour

Unsurprisingly, white is the preferred colour for bearings in the food industry. Many thermoplastics are made of this colour and should be considered for food applications in which there is direct contact with food. The colour allows quality controllers to quickly ensure that there is nothing foreign in the system that has led to a colour change in the bearing. It also ensures that no colour is transferred from the bearing to the food product  and that no visible foreign material can be detected in the final product.

Avoid lubrication

Food-grade lubricants can be used safely in food processing plants, without the concern that the lubricants may contain toxins that will be harmful in the food that they are in contact with. Bearings, including thermoplastic ones, often operate better with lubricants. However, many thermoplastic bearings offer the advantage of avoiding lubrication in the food-processing plant if required. This eliminates food particulates being caught in lubricant and ater contaminating the production chain. 

Choose bearings that are resistant to chemicals

Cleaning is of extreme importance in a food processing environment and the bearings that are chosen should not degrade when in contact with food chemicals or the cleaning chemicals that are used to ensure hygiene in the processing environment. Many thermoplastic bearings have demonstrated chemical resistance over a range of acids and alkalis and these may be preferred to untested bearings. 

Check optimal operating range

For many food-processing lines, steam cleaning is the advised method of cleaning. Numerous thermoplastics are able to operate at high temperature ranges and these should be chosen over plastics that cannot withstand high temperatures. It is advised that the temperature of the steam should be verified though, since some plastic bearings will melt if  exposed to high temperatures for sustained periods.

Ensure certification for food-grade applications

Various certifications are possible for plastic bearings and the polymers that make them. Among them are the FDA certification, common in the US, as well as various other certifications, including the National Test Laboratory certification of France, that apply elsewhere. These apply various aqueous tests, including distilled water, acetic acid and ethanol tests, as well as a fat test, that might include testing using sunflower oil. These are designed to ascertain the inertness of the polymers and the likelihood of a compound in the polymer being transferred to the food.

Avoid toxic components

Thermoplastics are often preferred to metallic components, including bronzes, which often contain lead and tin. This avoidance of tin and lead for the food-processing company has become important as consumers are becoming increasingly aware of the dangers of heavy  metals to tissues and organs.

Consider optimal bearing fit

For the food-processing company, there might, however, be other considerations other than the physical properties of a bearing that might be employed. For instance, optimal bearing fitment should also be considered, since food that remains in the running clearance of the bushing is likely to lead to contamination of the entire production chain. Optimal bearing fit requires that operating temperatures be taken cognisance of since some bearings expand when heated.

Benefit from smoothness

Food and beverages also tend to fall into any crack or hole on any surface in the production process. Some bearings are designed to have these features since these are necessary for smooth operation. Others have fewer moving parts and are constructed to form a single unit. Depending on the bearing required, thermoplastic bearings may offer advantages in that they tend to have smooth surfaces in which food particles are unlikely to accumulate. If they have been chosen for their smoothness and their lack of cavitation, it is important that they remain dent and damage free. To achieve this, improper forceful mounting, which might cause denting, wearing or cracking, should be avoided. Similarly, the bearing should not be extremely roughly treated during maintenance.

With Fortune Magazine noting that the yearly cost of food-related medical treatment, lost production and mortality caused by illness related to food-borne pathogens totals $55-million in the US, food processing companies are looking carefully at the parts of their production chain in which equipment is in contact with food. 

No particular study has identified bearings as a particular cause of food-borne pathogens, but bearing manufacturers are keen on ensuring that the risk of food-related illness or diseases associated with their particular componentry remains low.

Bearings, as with other types of equipment, have to be investigated to determine whether there is a possibility of incidental food contact or no possibility of contact. Once this is determined, bearings can be specified based on hygiene concerns appropriate for a given application.

With a rapidly urbanising and increasingly wealthier global population, which spends less time on food preparation due to increasing demands on its time, processed food demand is growing each year. 

This would not be a particular concern, except that food-related outbreaks and recalls are also growing. Food-borne illnesses and their risk to food consumers and food-processing companies cannot be underestimated and any opportunity to be more vigilant about hygiene should be taken.

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