Sumul or The Surat District Co-operative Milk Producers' Union Ltd, which is now renamed as The Surat-Tapi District Co-operative Milk Producers' Union Ltd, is one among the 21 district unions which acts as manufacturing units of dairy products for Gujarat Co-operative Milk Marketing Federation Limited, the marketers of Amul brand of products. Surat & Tapi District has been a Pioneer in India in channeling trade in Cotton and Milk through co-operatives. Before SUMUL stepped in, traditional Private Milk Traders were dominant in the area. The private trade was monopolizing the Milk market and exploiting both the Milk Producers and Consumers alike. The milk procurement price which used to be fixed by the traders (traditional Bhatias) was very low and was fluctuating from time to time at their sole discretion. These has capitalized on the absence of any infrastructure and processing facilities and has managed to keep producers from deriving equitable benefits from the marketable surplus generated. As such their income from milk was very low and they had no incentive for modern dairy farming. The farmers resented the system, but were helpless in the face of these traditional constraints and to their own lack of resourcelessness. Dairying on the other hand, was never popular with tribal's (a major rural population in the District) as practically no infrastructure existed for milk marketing in their talukas, inaccessibility to their villages as well as taboos regarding keeping of buffaloes prevented the entire population of tribal's from considering dairying as a source of income. The tribal's kept their cows to produce bullocks rather than milk, which was insufficient even to nurse the calves. Most of the tribal's were unaware of the usual milch breeds, what to say of Scientific Animal Husbandry?

Hygienic and pure milk was almost unknown in the market. In fact unbridled adulteration of milk was practiced by these traders to meet the growing demand of milk in the city. To salvage the poor producers from the clutches of these Private Traders, Organisation and integration of procurement, processing and marketing of milk and milk products by the producers themselves on a sound co. operative line was essential; this would also ensure elimination of middlemen, equitable distribution of benefits to Rural Milk Producers and indirectly to urban milk consumers as well. Hygienic and pure milk was almost unknown in the market. In fact unbridled adulteration of milk was practiced by these traders to meet the growing demand of milk in the city. To salvage the poor producers from the clutches of these Private Traders, Organisation and integration of procurement, processing and marketing of milk and milk products by the producers themselves on a sound co. operative line was essential; this would also ensure elimination of middlemen, equitable distribution of benefits to Rural Milk Producers and indirectly to urban milk consumers as well. Hence, The Surat-Tapi District Co. operative Milk Producers' Union Ltd.(formally known as The Surat District Co. operative Milk Producers' Union Ltd.), SUMUL is trade name and literally meaning sound price, came into existence on August 22, 1951.