Fluid milk

Milk has been a source for food for humans since the beginning of recorded history. Although the use of fresh milk has increased with economic development, the majority of consumption occurs after milk has been heated, processed, or made into butter. The milk industry became a commercial enterprise when methods for preservation of fluid milk were introduced. The successful evolution of the dairy industry from small to large units of production, ie, the farm to the dairy plant, depended on sanitation of animals, products, and equipment cooling faciUties health standards for animals and workers transportation systems constmction materials for process machinery and product containers pasteurization and sterilization methods containers for distribution and refrigeration for products in stores and homes. 

Pasteurization may be carried out by batch- or continuous-flow processes. In the batch process, each particle of milk must be heated to at least 63°C and held continuously at this temperature for at least 30 min. In the continuous process, milk is heated to at least 72°C for at least 15 s ia what is known as high temperature—short time (HTST) pasteurization, the primary method used for fluid milk. For milk products having a fat content above that of milk or that contain added sweeteners, 66°C is requited for the batch process and 75°C for the HTST process. For either method, foUowiag pasteurization the product should be cooled quickly to <7.2° C. Time—temperature relationships have been estabHshed for other products including ice cream mix, which is heated to 78°C for 15 s, and eggnog, which must be pasteurized at 69°C for 30 min or 80°C for 25 s. 

The leading states in milk production in decreasing order are Wisconsin, Minnesota, New York, California, and Pennsylvania. These states produce - 45% of the U.S. milk supply. Less than 5% of the total production is used on farms and the remainder is sold for commercial purposes. Whereas milk and cream were formerly shipped in 19-, 30-, or 38-L cans from the farm to the plant, in the 1990s most commercial production, particularly for fluid milk, is moved in bulk from the cows to refrigerated farm tanks to insulated bulk tmck tankers and to the manufacturing plant. The investment in equipment and the cost of hired labor are associated with large, capital-intensive production centers. 

In the United States, 62% of fluid milk production is used for manufactured products, mainly cheese, evaporated and sweetened condensed milk, nonfat dry milk, and ice cream. Evaporated and condensed milk and dry milk are made from milk only other ingredients are added to make ice cream and sweetened condensed milk. 

Nutritional Value of Milk Products. Milk is considered one of the principal sources of nutrition for humans. Some people are intolerant to one or more components of milk so must avoid the product or consume a treated product. One example is intolerance to lactose in milk. Fluid milk is available in which the lactose has been treated to make it more digestible. The consumption of milk fat, either in fluid milk or in products derived from milk, has decreased markedly in the 1990s. Whole milk sales decreased 12% between 1985 and 1988, whereas the sales of low fat milk increased 165%, and skimmed milk sales increased 48% (35). Nutritionists have recommended that fat consumed provide no more than 30 calories, and that consumption of calories be reduced. Generally, a daily diet of 2000—3000 cal/d is needed depending on many variables, such as gender, type of work, age, body responses, exercise, etc. Further, there is concern about cholesterol [57-88-5] and density of fat consumed. Complete information on the nutritive value of milk and milk products is provided on product labels (36) (see also Table 4). 

SANDERS M E (1993) Summary of the conclusion from a consensus panel of experts on health attributes on lactic cultures significance to fluid milk products containing cu txae%. JDiary Sci. 76 1819-28. 

Mitigation of Greenhouse Gas Emissions in the Production of Fluid Milk... 

The consumption of dairy products plays a significant role in providing high-quality protein, vitamins, minerals, and other bioactive compounds to the American diet. Dairy products are consumed fresh in the United States in the form of fluid milk, cheese, yogurt, butter, and ice cream. Dried and condensed products such as nonfat dried milk, whey, whey protein concentrates, and isolates are also produced which are used as ingredients to boost the nutritional and functional properties of a host of other food... 

The goals of most LCA have been limited to determination of the impact of the fluid milk process on GHG emissions and energy due to the availability of relevant data and guidelines from the IPCC and other government agencies. Data for conducting LCA of the other impact factors such as water use, aquatic toxicity, human health, and land use are scarce, but new initiatives to reduce the impact of dairy production in... 

FIGURE 2.2 Percentage contributed by each unit process toward the total U.S. fluid milk emissions (Thoma et al., 2010). 

The goal of the LCA is to understand the impact of the existing fluid milk supply chain on energy usage and GHG emissions, as well as the other impact categories provided that data are available, and to use the information as a roadmap for improvements to the process. The LCA also provides an environmental benchmark to identify points where improvements to the fluid milk supply chain may be made. 

FIGURE 2.3 System boundaries for lifecycle analysis of the fluid milk supply chain. 

A complete inventory analysis is conducted for each segment of the fluid milk supply chain to account for all the resource inputs and the primary and secondary sources of GHG emissions (CO2, CH4, and N2O) to air, water, and soil. The resource inputs include raw materials and energy. Their impact on GHG emissions are secondary sources of GHGs. The primary sources of GHG emissions are associated with farm operations. 

Because dairy cows or calves are culled for meat production, four different methods to allocate the enviromnental emissions at the farm and outside the boimdary of the fluid milk supply chain may be used (Cederberg and Stadig, 2003). The allocation method assumes, (1) no allocation is used and only milk production impacts the enviromnent ... 

GHG emissions for milk packaging are mainly CO2 and arise from the energy used to process and produce the raw materials, container formation which is done on site in fluid milk plants and from transportation of the raw material (Irmovation Center for U.S. Dairy, 2008 Keoleian and Spitzley, 1999 Spitzley et ah, 1997). 

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