What is exactly meant by a food proof bearing? There are in the food industry requirements to prevent that foodstuffs are contaminated by lubricants or cleaning agents. That requirement usually is met by using bearings that are well sealed or through other means that prevent harm to food like a construction that prevents leakage of lubricants onto foodstuffs and/or the use of so called "foodgrade" lubricants. The latter only contain ingredients that, when incidentally coming into food in minor quantities will, not consist a danger to human health when consumted incidentally.
A relatively new solution to prevent leakage from bearing lubricants into food is the use of MPL's (Microporous Polymeric Lubricants). Those are a combination of a high molecular weight polymer and a foodsafe baseoil that are introduced in the bearing in fluid form. After heating up the structure of the polymers becomes solid, more or less like a sponge. In the "sponge" the actual lubricant is contained; it becomes available for lubrication when the local contact pressure increases and is sucked back into the "sponge" when the pressure lowers again.Because all the available room in the bearing is completely filled, it also can give extra protection against ingress of water and cleaning agents from outside, resulting in a much longer bearing life without any need for maintenance after installing.
Some bearing manufacturers supply bearings that use materials that give better protection against corrosion. They may be useful in the food industry because machinery is cleaned quite often and prevention of water or cleaning agents getting in the bearing may be hard to prevent.
