Why is hygienic design of bearings critical to food safety

The hygienic design of food machinery plays an important role in controlling food safety. However, if the sanitary design of equipment parts is not considered, but only the general application of this concept, there may be a risk of bacterial breeding and transmission in the bearing, said Davide Zanghi, head of SKF sanitary design office.
The adverse effects of specific factors (such as corrosion, lubricant leakage, cleaning and automatic drying) on food safety should be considered in hygiene design, and appropriate design principles should be used to solve the problems. In essence, it is a design concept based on specific principles. Just as ergonomic design pays attention to the physiological needs of users, hygienic design focuses on preventing food pollution.
The European Union for health engineering and design (EHEDG) aims to promote the safe food production capacity of its members (including equipment manufacturers, food enterprises and research institutions) by improving health engineering design standards. SKF has joined EHEDG since 2006. In November 2016, the alliance held its biennial World Congress in Denmark, at which SKF again highlighted its long tradition of applying these design principles.
Design principle - treat bearing components with caution
In general, the EHEDG criterion considers that it is easy to retain food particles and water in the bearing, so the bearing is regarded as a potential hotbed for bacteria. The general recommendation is to ensure that the bearings are kept away from food contact areas.
This proposal is very consistent with the latest guidelines for the hygienic design of belt conveyors in the food industry. EHEDG focuses on two main challenges in safe food production in this field: how to avoid food contamination due to improper design of processing equipment and how to improve food safety without increasing the operating costs of cleaner production and hygiene. In fact, in the sanitary design of the whole system, people mainly focus on the system and main components (such as belt); However, insufficient attention is often paid to bearings and bearing units.
However, even if the bearings are not in direct contact with the food area, they are often near the food and have high-pressure water or dry cleaning systems. In this way, if bacteria exist, they may spread through the air and pollute food.
In order to minimize the risk of pollution, the hygienic design principle should be fully considered in the design of bearings. One of the most important principles of hygienic design is the ability of effective cleaning. This is actually easy to understand, but it is often not easy for bearings and bearing units in practice. First, the product should be made of non corrosive and non porous materials (such as stainless steel) or composite materials, and the shape is easy to clean, and the retained water can be drained automatically. The bearing unit shall have a filling base to avoid leaving gaps and breeding bacteria.
In general, the use of materials such as elastomers, composites and greases should comply with food safety directives and regulations. In all cases, grease leakage to food during operation should be avoided as far as possible.
**The method is that the bearing unit is equipped with efficient end caps to prevent pollutants and cleaning fluid from entering the bearing cavity, while allowing frequent visual inspection.
Other relevant areas include:
Avoid metal to metal contact between unit components and attachment surfaces
Supplementary lubrication should be avoided as far as possible
Long service life under very harsh operation and cleaning system
Hygienic design is fully applicable to food production and packaging machinery. However, the bearing is only one of many problem parts, and solving the bearing problem is only the * * step of improving the overall risk strategy.