Processing of Milk

Only a small amount of milk is sold to the consumer without processing (certified raw milk). The main part is subjected to a processing procedure shown schematically in Fig. 10.14. 

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Addition of acetic or mineral acid to skimmed milk to reduce the pH value to 4.6, the isoelectric point, will cause the casein to precipitate. As calcium salts have a buffer action on the pH, somewhat more than the theoretical amount of acid must be used. Lactic acid produced in the process of milk souring by fermentation of the lactoses present by the bacterium Streptococcus lactis will lead to a similar precipitation. 

Li CF, Bradley RL, Schultz LH. 1970. Fate of organochlorine pesticides during processing of milk into dairy products. J Assoc Anal Chem 53 127-193. 

Copley, M.S., Berstan, R., Dudd, S.N., Aillaud, S., Mukherjee, A.J., Straker, V., Payne, S. and Evershed, R.P. (2005d). Processing of milk products in pottery vessels through British prehistory. Antiquity 79 895-908. 

Release of fatty acids and some interesterification may also occur, but such changes are unlikely during the normal processing of milk. 

Advances in the processing and packaging of dairy foods have made possible the production of milk and other dairy foods that can be stored at room temperature for up to six months (Miller 1985). Ultra-high-temperature (UHT) processing of milk, combined with aseptic fil-... 

Burton, H. 1980. An introduction to the ultra-high temperature processing of milk and milk products. In Proceedings of the International Conference on UHT Processing and Aseptic Packaging of Milk and Milk Products. Department of Food Science, North Carolina State University, Raleigh, N.C. 

Walstra, P. 1969B. Studies on milk fat dispersion. III. The distribution function of globule size in cow s milk and the process of milk fat formation. Neth. Milk Dairy J. 23, 111-123. 

As indicated in Table 14.1, the water-soluble vitamins, e.g., thiamine, vitamin Bi2, and vitamin C, are susceptible to loss by heat processing of milk (Bender 1978 Harper 1976). UHT sterilization and... 

This mold generally refers to the buildup of the organism Geotrichum candidnm on food-contact factory equipment in processing plants. The term dairy mold is used in the processing of milk to identify this mold. 

POTENTIAL USE OF TRANSGLUTAMINASE IN PROCESSING OF MILK PROTEINS AND DAIRY... 

Dairy phospholipids are important structurally, because they are able to stabilise emulsions and foams, and to form micelles and membranes (Jensen and Newburg, 1995). Phospholipids also have the potential to be pro-oxidants, because they contain mono-unsaturated and poly-unsaturated fatty acids and have the ability to attract metal ions. Phosphatidyl ethanolamine binds copper strongly and is believed to be important in copper-induced oxidation in milk (O Connor and O Brien 1995 Deeth, 1997). The polyunsaturated fatty acids and metal ions accelerate lipid oxidation, especially when heat is applied hence, phospholipids can be degraded during the processing of milk. However, in dairy products, the situation is complex and it appears that phospholipids are able to act as either pro-oxidants or antioxidants, depending on the pH, ratio of water and phospholipid species (Chen and Nawar, 1991). 

Gaining an understanding of the molecular mechanism of crescent formation would advance our understanding of the process of milk fat globule secretion. Crescents are a route by which cellular constituents can... 

In a commercial response to the potential value of sphingolipids as functional food components, a patented process for preparing milk products enriched in both phospholipids and sphingolipids was developed (Dewet-tinck and Boone, 2002). These products are obtained by ultrafiltration of byproducts from the direct processing of milk or from the further processing of directly acquired byproducts. The ultrafiltration membrane used had a cut-off value ranging from 5,000 to 20,000 Da. 

Rizvi, S.S.H., Bhaskar, A.R. 1995. Supercritical fluid processing of milk fat Fractionation, scale-up, and economics. Food Technol. 49, 90-100. 

The processing of milk into various dairy products may result in vitamin C losses. Ice cream contains no vitamin C, nor does cheese. The production of powdered milk involves a 20 to 30 percent loss, evaporated milk a 50 to 90 percent loss. Bullock et al. (1968) studied the stability of added vitamin C in evaporated milk and found that adding 266 mg of sodium ascorbate per kg was sufficient to ensure the presence of at least 140 mg/L of ascorbic acid during 12 months of storage at 21 °C. Data on the stability of vitamin C in fortified foods have been assembled by deRitter (1976) (Table 9-15). 

It will be noted that K-casein is the only monomer subunit that contains a disulfide group, and this is undoubtedly responsible for its ability to self aggregate as well as to interact with g-lactoglobulin during heat processing of milk. 

Fat or lipid materials and calcium-lipid complexes also contribute to fouling and flux decline in membrane processing of milk or whey. The transport properties of the feed stream and the changes they undergo as the concentration process proceeds also affect the rate of permeation. At high concentrations, the increased fluid viscosity near the membrane surface limits back-diffusion of solids from the polarized layer to the bulk phase, thereby, depressing flux rate [46]. 

In short, as Last pointed out, the term preventive medicine in its broadest sense implies a more personal encounter (immunization, screening, health education) between the individual and the medical or pharmaceutical personnel than that entailed in health protection activities (potabilization and fluoridation of mains water, processing of milk, sewage disposal, etc.), since in the latter case the professionals have no contact at all with the user. 

C. Vetier, M. Bennasar and B. Tarodo de la Puente, Study of the fouling of a mineral microfiltration membrane using scanning electron microscopy and physicochemical analysis in the processing of milk. /. Dairy Res., 55 (1988) 381. 

Dalgleish, D.G., Tosh, S.M., and West, S. (1996). Beyond homogenization The formation of very small emulsion droplets during the processing of milk by a microfluidizer. Neth. Milk Dairy J. 50,135-148. 

McMahon, D.J., Yousif, B.H., and Kalab, M. (1993). Effect of whey protein denaturation on structure of casein micelles and their rennetability after ultra-high temperature processing of milk with or without ultrafiltration. Int. Dairy J. 3, 239-256. 

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