Pasturization technique_zia_pau

Pasteurization Technique presentation-Primeasia University, Dhaka-Bangladesh

1. Welcome To Pasteurizaion Technique Department of Public Health Nutrition Primeasia University

2. Pasteurization Technique Pasteurization is a process that kills microbes (mainly bacteria ) in food and drink , such as milk , juice , canned food , and others. Pasteurization involves heating food to a temperature that kills disease causing microorganism and substantially reduces the levels of spoilage organisms. Pasteurization is not intended to kill all micro-organisms in the food. Instead pasteurization aims to reduce the number of viable pathogens so they are unlikely to cause disease (assuming the pasteurized product is stored as indicated and consumed before its expiration date). Heat also destroy enzymes that make milk spoil, so pasteurized milk drinkable for longer time.

3. History: It was invented by French scientist Louis Pasteur during the nineteenth century. In 1864 Pasteur discovered that heating beer and wine was enough to kill most of the bacteria that caused spoilage , preventing these beverages from turning sour. The process achieves this by eliminating pathogenic microbes and lowering microbial numbers to prolong the quality of the beverage. Today, pasteurisation is used widely in the dairy industry and other food processing industries to achieve food preservation and food safety . [2] Unlike sterilization , pasteurization is not intended to kill all microorganisms in the food. Instead, it aims to reduce the number of viable pathogens so they are unlikely to cause disease (assuming the pasteurized product is stored as indicated and is consumed before its expiration date ).

4. Objectives of Pasteurization: To Kill all the pathogens that may enter the milk & be transmitted to people. To Improve the keeping quality of milk. To Increase the shelf-life of products. To destroy microorganisms that would interfere with the activities of desirable organisms.

5. Efficiency of Milk Pasteurization: or The % of reduction of numbers of microorganisms in milk depends on: Temperature of pasteurization. The holding time. The total number of microbial load that are sporeformers or thermoduric organisms.

6. Methods of Pasteurization Milk Pasteurization: There are four common types of milk pasteurization that vary with temperature and time the milk is held at that temperature. Vat Pasteurization : High Temperature/Short Time (HTST) Ultra-pasteurization (UP) Ultra-High-Temperature (UHT) Other Methods (Used for other foods ) Flash pasteurization Steam Pasteurization Irradiation Pasteurization

7. Vat Pasteurization : This is the type typically used by farmers for their own consumption, and is the least harmful to the milk's nutrients. The milk is heated to 145° F and held at that temperature for 30 minutes. Such milk is used to prepare milk for culturing (cheese, yogurt, etc), as it is the least destructive to milk’s proteins. Average shelf life is 7 - 10 days. High Temperature/Short Time (HTST) The milk is heated to 161° F and held at that temperature for 15 seconds. This is the most common method of regular pasteurization used by local dairies, with about the same shelf life as vat process.  Ultra-pasteurization (UP) The milk is heated to 280° F for 2 seconds. Note this is above boiling, which means that high pressure must be applied to the milk to achieve this temperature, and is destructive to its nutritional quality. This method is used because it extends the refrigerated shelf-life of the milk to 60 - 90 days, and is the method of choice for national or regional milk brands because it allows time for warehousing and shipment of milk.  Ultra-High-Temperature (UHT ) The milk is heated to 280° to 302° F for 1 or 2 seconds followed by packaging in airtight containers. It allows storage without refrigeration for up to 90 days. Again, high pressure is required to reach this high temperature.

8. Other Methods (Used for other foods) Flash pasteurization used for drink boxes and other liquids that can be stored for long periods of time without refrigeration. This method involves high temperature for 3 to 15 seconds, followed by cooling and packaging. Very similar to UHT treatment of milk (see above). Steam Pasteurization used to kill E. coli, Salmonella and Listeria in beef carcasses. This results in surface temperatures of about 200° F.  Irradiation Pasteurization used on such foods as meats (especially prepared meats, sausages and cold cuts), spices, and produce (such as almonds, etc). The food is exposed to a type of radiation known as gamma rays

9. Process flow Diagram Pasteurized milk

10. Effects of pasteurization 1) Nutritional 2) Physical 3) Microbial 4) Enzymatic Nutritional - Although the process of pasteurization has beneficial effects, it has some nutritional drawbacks as well. Some research findings have been cited below to further elucidate the point. The relation of the vitamins to obstetrics, American Journal of Obstetrics and Gynecology, 29.5:759. May, 1935. "Pasteurization of milk destroys about 38% of the B complex according to Dutcher and his associates..." -Lewis, L.R.

11. Physical - Pasteurization does not alter the flavour or taste of milk The flavouring compounds already present in milk are also not destroyed. There is no colour or smell alteration too. Microbial - The main aim of pasteurization was to eliminate any disease producing organisms, reduce the total bacterial count and improve the keeping quality. The process destroys all pathogenic bacteria but vegetative organism and spores still remain in the suspension. Thus pasteurization is not an alternative to sterilization. 99% of bacteria, fungi, yeasts and moulds are killed. Enzymatic - Denaturation of alkaline phosphatase, which is also used as an indicator to the completion of pasteurization, is deactivated. It also reduces the lipase activity

12. Refferences: http://Pasturization/Pasteurization%20-%20Wikipedia.htm#Process http://essentialstuff.org/wp-content/uploads/2009/08/foodSafety-Pasteurization_chaug.pdf http://www.medindia.net/patients/patientinfo/latest-publication-and-research-on-pasteurizationofmilk.htm http://www.extension.umn.edu/agriculture/dairy/calves-and-heifers/pasteurization-considerations-for-dairy-calves.pdf http://science.howstuffworks.com/life/cellular-microscopic/pasteurization4.htm https://www.extension.umn.edu/agriculture/dairy/calves-and-heifers/pasteurization-considerations-for-dairy-calves.pdf Food microbiology book , 4 th edition, William C. Frazier & Dennis C.Westhoff, chapter 18, page:279-282

13. Thanks You Every Body Prepared by__ Md Zia Uddin, 131-485-034 Farhana Rifat Akul, 131-484-034 Department of Public Health Nutrition Primeasia Univesrity Dhaka-Bangladesh