Condensed milk production

From experience it has been established that the sensory threshold for coffee creamer and condensed milk products is on the order of 0.1 mg/kg (ppm) of styrene in the product. This observation is only partly supported by threshold values from the literature in Table 14-2 where values range from 0.2 ppm for 3 % yogurt, 1.2 ppm for 3.8 % fat milk and 2-5 ppm for condensed milk. This points out two problems with threshold concentration values caused by the way they are determined (e.g. experimental methods) and the definition of the threshold value being the value at which the substance is correctly identified by 50 % of the panelists (versus other possible ways of measur-ing/defining the taste threshold). 

The ketone 2 heptanone has been identified as contnbuting to the odor of a number of dairy products including condensed milk and cheddar cheese Describe a synthesis of 2 heptanone from acetylene and any necessary organic or inorganic reagents... 

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. 

Evaporated milk is a Hquid product obtained by the partial removal of water only from milk. It has a minimum milk-fat content of 7.5 mol % and a minimum milk-solids content of 25.0 mol %. Evaporated skimmed milk is a Hquid product obtained by the partial removal of water only from skimmed milk. It has a minimum milk-solids content of 20.0 mol %. Sweetened condensed milk is a product obtained by the partial removal of water only from milk with the addition of sugars. It has a minimum milk-fat content of 8.0 mol % and a minimum milk-solids content of 28.0 mol %. Skimmed sweetened condensed milk is a product obtained by the partial removal of water only from skimmed milk with the addition of sugars. It has a minimum milk-solids content of 24.0 mol %. AH may contain food additives (qv) as stabilizers, in maximum amounts, including sodium, potassium, and calcium salts of hydrochloric acid at 2000 mg/kg singly citric acid, carbonic acid, orthophosphoric acid, and polyphosphoric acid at 3000 mg/kg in combination, expressed as anhydrous substances and in the evaporated milk carrageenin may be added at 150 mg/kg. 

Large quantities of evaporated milk are used to manufacture ice cream, bakery products, and confectionery products (see Bakery processes and LEAVENING agents). When used for manufacturing other foods, evaporated milk is not sterilized, but placed in bulk containers, refrigerated, and used fresh. This product is caHed condensed milk. Skimmed milk may be used as a feedstock to produce evaporated skimmed milk. The moisture content of other Hquid milk products can be reduced by evaporation to produce condensed whey, condensed buttermilk, and concentrated sour milk. 

The preferred source of milk solids for making toffee and caramel products remains sweetened condensed milk. This was one of the earliest ways of producing a stable product from milk. Both full cream and skimmed milk forms are used. The advantage of skimmed sweetened condensed milk is that the milk fat can be replaced with vegetable fat if so required. Products made from sweetened condensed milk are... 

Evaporated milk is a more modern product than sweetened condensed milk. It is not normally used in food manufacture. This material has no technical or economic advantages over milk powder. 

Maillard products are not only formed during cooking and other heat processing of foods, but also accumulate in some products that are rich in proteins and reducing sugars, e.g. condensed milk during months of storage at... 

In-container or UFIT-sterilized concentrated milks sweetened condensed milk Whole milk powders infant formulae dietary products... 

Sweetened condensed milk. Crystallization of lactose occurs in sweetened condensed milk (SCM) and crystal size must be controlled if a product with a desirable texture is to be produced. As it comes from the evaporators, SCM is almost saturated with lactose. When cooled to 15-20°C, 40-60% of the lactose eventually crystallizes as a-lactose hydrate. There are 40-47 parts of lactose per 100 parts of water in SCM, consisting of about 40% a-and 60% /1-lactose (ex-evaporator). To obtain a smooth texture, crystals with dimensions of less than 10 /an are desirable. The optimum temperature... 

Calculated from metric tons produced and converted to pounds milk equivalent with factors 21.2 lb of milk/pound of butter, 10 lb/lb of cheese and 11 lb/lb of NFDM. Percent of production calculated by dividing total pounds of milk product by total pounds of milk produced x 100 (Milk Industry Foundation, 1981). rfProduction figures do not total 100% because other milk products (frozen desserts, condensed, etc.) are not included, and there is an overlap of milk used for both butter and nonfat dry milk, as well as whey butter from cheese. 

Plain condensed milk or concentrated milk has the same standard of identity in the United States as evaporated milk, except that it is not given additional heat processing after concentration. This product is shipped in bulk containers and is perishable. Technology is available to produce it in a sterile or almost sterile manner, and its extended shelf life gives it a potential, but as yet undeveloped, market as a source of beverage milk. Whole milk can be successfully concentrated up to 45% total solids, and these higher concentrations have found some use in the bulk product market. 

Sweetened condensed milk is made by the addition of approximately 18% sugar to whole milk, followed by concentration under vacuum to approximately one-half its volume. The product is canned without sterilizing, for the sugar acts as a preservative. 

Frozen desserts made from sugar, water, fruit acid, color, fruit or fruit flavoring, and stabilizer, and containing a small amount of milk solids added in the form of skim milk, whole milk, condensed milk, or ice cream mix, are known as sherbets. Federal standards for these products are included in Table 2.7. 

Lipid autoxidation in fluid milk and a number of its products has been a concern of the dairy industry for a number of years. The need for low-temperature refrigeration of butter and butter oil, and inert-gas or vacuum packing of dry whole milks to prevent or retard lipid deterioration, in addition to the loss of fluid and condensed milks as a result of oxidative deterioration, have been major problems of the industry. The autoxidation of milk lipids is not unlike that of lipids in other... 

Storage Temperature. The role of storage temperature in the oxidative deterioration of dairy products is anomalous. Dunkley and Franke (1967) observed more intense oxidized flavors and higher TBA values in fluid milks stored at 0°C than at 4° and 8°C. The flavor intensity and the TBA values decreased with increasing storage temperature. Other conditions being equal, condensed milk stored at - 17°C is more susceptible to the development of oxidized flavor than is condensed milk maintained at -7°C (Parks 1974). 

Time-temperature relationships have been established by various workers as being optimum for preventing or retarding the development of oxidized flavors in dairy products cream, 88 °C for 5 min condensed milk, 76.5°C for 8 min dry whole milk, preheated at 76.5°C for 20 min and frozen whole milk, 76.5°C for 1 min (Parks 1974). Few, if any, instances of a tallowy flavor have been reported in evaporated... 

The crystallization principles previously discussed are applied in processing dairy products, such as sweetened condensed milk, instant milk powder, stabilized whey powders, lactose, and ice cream. 

Hunziker, O. F. 1949. Condensed Milk and Milk Products, 6th ed. Published by the author, La Grange, Illinois. 

M. miehei rennet is the most heat stable of all the commonly used milk-clotting enzymes (Thunell et al 1979). None is destroyed during Cheddar cheese manufacture although, like M. pusillus var. Lindt rennet, less than 2% remains active in the cheese (Harper and Lee 1975 Holmes et al. 1977). It remains active in the whey and is concentrated in condensed whey products. 

Milk yields principally the two highly important products, butter and cheese both of these and also milk itself, including preserved and condensed milks, are dealt with in the present chapter. 

Condensed milks are mostly condensed to one-third of their volume. Their composition varies somewhat, atcording to the degree of concentration and to the addition of sugar (see later). Good products should be slightly yellowish, should have no unpleasant smell or cheesy flavour and should be homogeneous and show no clots, fat drops or crystals (lactose). 

Condensed milk is usually sold in soldered tins. The analysis should be made immediately after opening, since such products readily change, especially when little or np sugar has been added. Of special importance are tests for antiseptics and other preservatives (see Milk, No. 11) and heavy metals, and bacteriological examination. 

This is the procedure employed in the analysis of many products containing sugar (see later in this chapter) and of spirituous liquors, in the determination of saccharose and lactose in condensed milk (q.v.), etc. 

A procedure of this kind, with slight variations, is applied to the analysis of winee containing saccharose and also of condensed milk in which invert sugar as well as saccharose is present this is described in dealing with these products. 

These include mainly crystallised fruits, preserved fruits, jams, chocolates, sweetmeats, biscuits, effervescent citrate of magnesia, honey, condensed milk, liqueurs and sweet wines. Certain of these products are dealt with in other places, condensed milk, liqueurs and sweet wines, for instance, in the chapters dealing respectively with milk, spirits and liqueurs, and wines. The others are treated below, special attention being paid to the determination of the sugars. 

An example of a product that has had styrene taint problems over the years has been dairy products such as coffee creamer and condensed milk packed in thermo-formed PS single serve portion pack containers holding 5-10 g of product. The high package mass and surface area ratio to product and high fat content of the product make this package/product system a challenging system to optimize. 

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