1. Milk

2. What is milk? Milk is a white liquid produced bythe mammary glands of mammals. It isthe primary source of nutrition foryoung mammals before they are ableto digest other types of food. Early-lactation milk contains colostrum, whichcarries the mothers antibodies to thebaby and can reduce the risk of manydiseases in the baby. 3. What is milk? Milk derived from cattle species is animportant food with many nutrients.The precise nutrient composition of rawmilk vary by species and by a numberof other factors, but it containssignificant amounts of saturatedfat, protein and calcium as wellas vitamin C. Cows milk hasa pH ranging from 6.4 to 6.8, making itslightly acidic. 4. History of milk 5. History In 1856, Gail Borden received the firstUnited States and English patents forcondensed milk. Gail Borden patented amethod for making condensed milk byheating it in a partial vacuum. In1861, Gail Borden opened a condensedmilk plant and cannery in Wassaic, NewYork. 6. History In 1863, Louis Pasteur inventedpasteurization, a method of killing harmfulbacteria in beverage and food products. In1891, the first U.S. milk processing plant toinstall pasteurization equipment was theSheffield Farms Dairy in Bloomfield, NewJersey. They used a German-madepasteurizer. In 1908, Chicago became thefirst major American city to pass a lawrequiring commercial milk to be pasteurizedmilk. 7. History In 1878, Doctor Gustav De Laval invented thecontinuous centrifugal cream separator. In 1884, Doctor Hervey Thatcher ofPotsdam, New York invented the first glassmilk bottle called Thatchers Common SenseMilk Jar, which was sealed with a waxed paperdisk. Victor Farris was the inventor of the paper milkcarton. In 1932, plastic-coated paper milkcartons were introduced commercially. In1964, the all plastic milk container wascommercially introduced. 8. Sources of milk 9. Sources Aside from cattle, many kindsof livestock provide milk used by humansfor dairy products. These animals include: Camel Donkey Goat Horse Reindeer Sheep Water Buffalo (Carabao) Yak 10. Components ofmilk 11. Components Lipids including phospholipids and also fatty acids Proteins Caseins - Special types of proteins found in milk thatare bound to each other by calcium and orphosphorus ions. Carbohydrates includinglactose, glucose, galactose, and otheroligosaccharides. VitaminsA, B6, B12, C, D, K, E, thiamine, niacin, biotin, riboflavin, folates, and pantothenic acid Mineral Salt forms ofpotassium, sodium, magnesium, calcium, phosphates,chlorides, and citrates. Traces of sulfates andcarbonates are found. Iron is present in small amount.Iodides are also found in small amounts. 12. Types of milk 13. Which milk are available? Whole milk Natural whole milk is milk with nothing added orremoved. Whole standardised milk is whole milkstandardised to a minimum fat content of 3.5%. Whole homogenised milk is identical in fat andnutrient content to whole standardised milkhowever it has undergone a specific processknown as homogenisation which breaks up thefat globules in the milk. This spreads the fatevenly throughout the milk and prevents acreamy layer forming at the top. 14. Which milk are available? Semi-skimmed milk Semi skimmed milk is the most popular type ofmilk in the UK with a fat content of1.7%, compared to a minimum of 3.5% in wholestandardised milk and 0.1% in skimmed milk. Skimmed milk Skimmed milk has a fat content of between 0-0.5% and an average fat content of0.1%. Skimmed milk therefore has nearly all thefat removed. It contains slightly more calcium than whole milkand lower levels of fat solublevitamins, particularly vitamin A, as this is lostwhen the fat is removed. 15. Which milk are available? 1% fat milk The EU regulations for milk classification previously dividedmilk into three categories defined by the fat content;whole, semi-skimmed or skimmed. Prior to 2008, any milkthat contained a different fat content was defined as a milkdrink. On the 1st of January 2008 new regulations came into forceto facilitate consumer choice. Now any milk with a fatcontent other than those laid out can also be considered asmilk, provided that its fat content is clearly indicated onthe packaging in the form of .% fat. However, thesemilks cannot be described as whole, semi-skimmed orskimmed. Following this change in regulation 1% fat milk is nowoffered to consumers who like the taste of semi-skimmed, but want to enjoy milk with a lower fat content. 16. Which milk are available? Organic milk Organic milk comes from cows that havebeen grazed on pasture that has nochemical fertilisers, pesticides oragrochemicals used on it. The producers must register with anapproved organic body and are subject toregular inspection. Once the cows have been milked, the milkis treated in exactly the same way asregular pasteurised milk. 17. Which milk are available? Jersey and Guernsey milk Channel Island milk is produced from Jerseyor Guernsey breeds of cow and has aparticularly rich and creamy taste. It tends to be slightly higher in calories andfat than regular whole milk and also has ahigher content of fat soluble vitamins -particularly vitamin A which is important forthe promotion and maintenance of healthygrowth and development. Jersey and Guernsey milks tend to have avisible cream line and are commonly found insupermarkets as breakfast milk. 18. Which milk are available? Flavoured milk The flavoured milk market is one of the fastest growing dairy sectors. There are a wide variety of flavours and consistencies to cater for all ages and tastes with a choice of long-life (i.e. Ultra Heat Treated or sterilised) or fresh flavoured milk. Most flavoured milk products are produced using reduced fat milk varieties and usually have a fat content of around 1%. The most popular flavours are chocolate, strawberry and banana however more sophisticated flavours such as peach, mocha or products made with real Belgian and Swiss chocolate have been developed for the more adult market. In comparison with plain milks, flavoured milks tend to have slightly higher sugar content, however studies have suggested that they are still a favourable option for children and teenagers as they provide a wide range of beneficial nutrients. 19. Which milk are available? Heat treated milks Approximately 99% of milk sold in the UK is heat-treated, to kill harmful bacteria and to improve itsshelf life. Sterilised milk Sterilised milk is available in whole, semi skimmedand skimmed varieties. It goes through a moresevere form of heat treatment, which destroysnearly all the bacteria in it. Firstly the milk is pre-heated to around 50oC, thenhomogenised (see below for a brief outline ofhomogenisation), after which it is poured intoglass bottles which are closed with an airtightseal. 20. Which milk are available? UHT milk UHT or ultra heat treated milk is a form of milk thathas been heated to a temperature of at least 135C inorder to kill off any harmful micro-organisms (e.g.harmful bacteria) which may be present in the milk.The milk is then packaged into sterile containers. All milk that is available for sale to consumers throughsupermarkets and milkmen must be pasteurised i.e.heated to 71.7C in order to make it safe forconsumers and improve its shelf life. However UHTmilks have a longer shelf life as a result of the highertemperatures to which they are heated and thepackaging used to store them. UHT milk is available in whole, semi skimmed andskimmed varieties. 21. Which milk are available? Evaporated milk Evaporated milk is a concentrated, sterilised milkproduct. It has a concentration twice that of standardmilk. The process of producing evaporated milk involvesstandardising, heat treating and evaporating the milkunder reduced pressure, at temperatures between60C and 65C. Condensed milk Condensed milk is concentrated in the same way asevaporated milk, but with the addition of sugar. This product is not sterilised but is preserved by thehigh concentration of sugar. It can be made fromwhole milk, semi skimmed or skimmed milk. 22. Which milk are available? Untreated (raw) milk All milk sold via the supermarkets and milkmenhas to be heat-treated (pasteurised) to killharmful bacteria. However, untreated milk can bebought direct form a limited number of farmdistributors in England and Wales. Filtered milks Filtered milk goes through an extra, fine filtrationsystem, which prevents souring bacteria frompassing through. The nutritional content of the milk is unaffectedbut the shelf life is increased. The processes involvedinclude, microfiltration, ultrafiltration andnanofiltration. 23. Which milk are available? Dried milk powder Milk powder is produced by evaporating the waterfrom the milk using heat. The milk ishomogenised, heat treated and pre-concentratedbefore drying. There are a number of ways to produce dried milkpowder including spray drying and roller drying. In the most commonly used spray drying process, theconcentrated milk is introduced into a chamber(usually as a fine mist) through which hot air iscirculating. The droplets of milk soon lose their waterand fall to the floor as fine powder. Skimmed milk powder can be mixed easily with water;however whole milk isnt easily reconstituted due to itshigher fat content. 24. Industrialprocessesinvolving milk 25. Milk Processing Clarification is the process of removing undesirableforeign matter and bacteria from the milk. Separation is the process of dividing the milk into itscomponent parts mainly skimmed milk, cream, and othereffluents for further individual processing and tomaximize product variety and yield, also determineswhich process each would undergo. Standardization is the industrial adjustment of milk orcream fat content to a precisely specified or desiredvalue. Pasteurization is the process of heating liquids orfoods to kill microorganisms (such asBrucella, Campylobacter, E. coliO157:H7, Listeria, Mycobacterium bovis, Salmonella, andYersinia) that can cause disease. It was developed byLouis Pasteur in 1864. 26. Milk Processing Methods for Milk Pasteurization High Temperature Short Time Treatment. Milk ispasteurized at 161 F for 15 seconds. Low Temperature Long Time Treatment. Milk ispasteurized at 145 F for 30 minutes. Flash Pasteurization. This type of pasteurization, whichinvolves high temperature for 3 to 15 seconds followed bycooling and packaging, is used for drink boxes and otherliquids that can be stored for long periods of time withoutrefrigeration. Ultrapasteurization. Heating milk or cream to 280 F for 2seconds can extend the refrigerated shelf life of milk from60 to 90 days. Ultra-High Temperature Pasteurization. Heating milkto 280 to 302 F for 1 or 2 seconds followed by packaging inairtight containers allows storage without refrigeration forup to 90 days. 27. Milk Processing Homogenization allows milkmanufacturers to combine the cream and milkso that it does not separate. The main goalbehind milk homogenization is to reduce thesize of the fat molecules in milk becausesmaller molecules tend to stay suspended inthe body of the liquid. Only large globulesfloat to the top. Fortification is the process of introducingadditional vitamins and minerals to the milk toimprove product quality. 28. Milk Processing Diagram