Hi Salu, we often find organic growths in lubricating oil samples, if there is free water and a little bit of heat any fungus spores or bacteria that gain entry with the water will readily grow in the application living in the water and feeding on the oil, (like Fuel Bug) if no water then more difficult for organic growths to occur, if these growths occur in a food plant that can be serious and every sample that we see organic growths in and detect a "dead horse" aroma on from a food plant receives advice that we think the oil should be changed and water prevented from entry, with food grade lubricants because they are applied due the possibility that incidental contact could occur with food, biocides are not usually an option and because water is usually present to enable the growth in the first instance water should be kept out of the lubricant anyway to prevent premature bearing damage,
Regards Rob S