Three trials were made, in which mammary tissues obtained under hygienic conditions were stored together with discharged milk at 4 degrees and 20 degrees C. Bacteriological, histological, organoleptic and pH studies were done to assess the keeping qualities and spoilage of these tissues. The results of these studies showed that mammary tissues stored at 4 degrees C together with discharged milk will remain stable for a maximum period of four days. Inadequate chilling or failure to chill (as is often the case on storage in receptacles in the field) is inadmissible because of spoilage (one day) and the rapid growth of Staphylococcus aureus. The discharged milk stored along with the mammary tissues will have an adverse effect on the keeping qualities of the tissues. Spoilage of mammary tissues may occur as well in the superficial layer as in the deeper layers as both the surface and the subjacent tissues harbour bacteria. Penetration of bacteria from the surface to the deeper tissues does not occur. The paper concludes with recommendations based on previous studies and above mentioned investigation regarding good manufacturing practices where the production, storage and treatment of bovine udders are concerned.